<PAGE>   1
                                                                     EXHIBIT 4.1











                                RIGHTS AGREEMENT

                                     BETWEEN

                         LARGE SCALE BIOLOGY CORPORATION

                                       AND

                          EQUISERVE TRUST COMPANY, N.A.

                                 AS RIGHTS AGENT






                           DATED AS OF APRIL 27, 2001

<PAGE>   2

                               TABLE OF CONTENTS


<TABLE>
<CAPTION>
                                                                                PAGE
                                                                                ----
<S>          <C>                                                                <C>
Section 1.   Certain Definitions..................................................1

Section 2.   Appointment of Rights Agent..........................................4

Section 3.   Issue of Right Certificates..........................................5

Section 4.   Form of Right Certificates...........................................6

Section 5.   Countersignature and Registration....................................6

Section 6.   Transfer, Split Up, Combination and Exchange of Right
             Certificates; Mutilated, Destroyed, Lost or Stolen Right
             Certificates.........................................................7

Section 7.   Exercise of Rights; Purchase Price; Expiration Date of Rights........8

Section 8.   Cancellation and Destruction of Right Certificates...................9

Section 9.   Status and Availability of Preferred Shares..........................9

Section 10.  Preferred Shares Record Date.........................................9

Section 11.  Adjustment of Purchase Price, Number of Shares or
             Number of Rights....................................................10

Section 12.  Certificate of Adjusted Purchase Price or Number of Shares..........16

Section 13.  Consolidation, Merger or Sale or Transfer of Assets
             or Earning Power....................................................16

Section 14.  Fractional Rights and Fractional Shares.............................17

Section 15.  Rights of Action....................................................18

Section 16.  Agreement of Right Holders..........................................18

Section 17.  Right Certificate Holder Not Deemed a Stockholder...................19

Section 18.  Compensation and Indemnity of the Rights Agent......................19

Section 19.  Merger or Consolidation or Change of Name of Rights Agent...........20

Section 20.  Rights and Duties of Rights Agent...................................20

Section 21.  Change of Rights Agent..............................................22

Section 22.  Issuance of New Right Certificates..................................23
</TABLE>



                                      -i-

<PAGE>   3

                               TABLE OF CONTENTS


<TABLE>
<CAPTION>
                                                                                PAGE
                                                                                ----
<S>          <C>                                                                <C>
Section 23.  Redemption..........................................................23

Section 24.  Exchange............................................................24

Section 25.  Notice of Certain Events............................................25

Section 26.  Notices.............................................................26

Section 27.  Supplements and Amendments..........................................26

Section 28.  Successors..........................................................27

Section 29.  Benefits of this Agreement..........................................27

Section 30.  Severability........................................................27

Section 31.  Governing Law.......................................................27

Section 32.  Counterparts........................................................27

Section 33.  Descriptive Headings................................................27

Section 34.  Entire Agreement....................................................27

             Signatures..........................................................28

Exhibit A -- Form of Certificate of Designations of Series A Junior
             Participating Preferred Stock

Exhibit B -- Form of Right Certificate

Exhibit C -- Summary of Rights to Purchase Preferred Shares
</TABLE>



                                      -ii-
<PAGE>   4

                                RIGHTS AGREEMENT

        This Agreement, dated as of April 27, 2001 between Large Scale Biology
Corporation, a Delaware corporation (the "COMPANY"), and Equiserve Trust
Company, N.A., a national banking association (the "RIGHTS AGENT").

        The Board of Directors of the Company has authorized and declared a
dividend of one preferred share purchase right (a "RIGHT") for each Common Share
(as hereinafter defined) of the Company outstanding at the Close of Business (as
hereinafter defined) on May 4, 2001 (the "RECORD DATE"), each Right
representing the right to purchase one one-hundredth of a Preferred Share (as
hereinafter defined), upon the terms and subject to the conditions herein set
forth, and has further authorized and directed the issuance of one Right with
respect to each Common Share that shall become outstanding (i) between the
Record Date and the earliest of the Distribution Date, the Redemption Date and
the Final Expiration Date (as such terms are hereinafter defined) or (ii)
following the Distribution Date and prior to the Redemption Date or Final
Expiration Date, pursuant to the exercise of stock options or under any employee
plan or arrangement or upon the exercise, conversion or exchange of other
securities of the Company, which options or securities were outstanding prior to
the Distribution Date.

        Accordingly, in consideration of the premises and the mutual agreements
herein set forth, the parties hereto hereby agree as follows:

        SECTION 1. Certain Definitions. FOR PURPOSES OF THIS AGREEMENT, THE
FOLLOWING TERMS HAVE THE MEANINGS INDICATED:

               (a) "ACQUIRING PERSON" shall mean any Person who or which,
together with all Affiliates and Associates of such Person, shall be the
Beneficial Owner of 15% (the "DESIGNATED PERCENTAGE") or more of the Common
Shares of the Company then outstanding, but shall not include (i) the Company,
(ii) any Subsidiary of the Company, (iii) any employee benefit plan of the
Company or any Subsidiary of the Company or (iv) any entity holding Common
Shares for or pursuant to the terms of any such plan. Notwithstanding the
foregoing,

                      (i) No Person shall become an Acquiring Person if the
Board of Directors of the Company determines in good faith that a Person who
would otherwise be an Acquiring Person has become such inadvertently, and such
Person as promptly as practicable takes such actions as may be necessary so that
such Person would no longer be considered an Acquiring Person.

                      (ii) No Person shall become an Acquiring Person as the
result of an acquisition of Common Shares by the Company which, by reducing the
number of shares outstanding, increases the proportionate number of shares
beneficially owned by such Person and such Person's Affiliates and Associates to
the Designated Percentage or more of the Common Shares of the Company then
outstanding; provided, however, that if a Person, together with such Person's
Affiliates and Associates, shall become the Beneficial Owner of the Designated
Percentage or more of the Common Shares of the Company then outstanding by
reason of share purchases by the Company and such Person, together with its
Affiliates and Associates, shall, after public announcement of such share
purchases by the Company, become the Beneficial



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<PAGE>   5

Owner of any additional Common Shares of the Company, then such Person shall be
deemed to be an "ACQUIRING PERSON."

                      (iii) Neither Technology Directors II, LLC nor any
Affiliate or Associate thereof, including without limitation John W. Maki, John
J. O'Malley and Kevin Ryan (collectively, the "TECHNOLOGY PERSONS"), shall be an
Acquiring Person; provided, however, that the Technology Persons, or any of
them, shall become an Acquiring Person if, on any date, such Technology Person
or Technology Persons shall be (i) the Beneficial Owner of (A) one percent (1%)
or more of the Common Shares of the Company then outstanding ("OUTSTANDING
SHARES") in addition to (B) the Common Shares Beneficially Owned by the
Technology Persons outstanding on the date hereof (it being understood that any
transfer of such Common Shares to a third party after the date hereof will
reduce the aggregate percentage of the Outstanding Shares represented by the
Common Shares included in clauses (A) and (B) above), and (ii) the Beneficial
Owner of the Designated Percentage or more of the Common Shares of the Company
then outstanding. For purposes of the foregoing calculation, Common Shares or
options or rights to acquire Common Shares pursuant to the Company's option and
employee stock purchase plans which are Beneficially Owned by any Technology
Person who is also an employee or director of the Company shall be excluded from
the number of Common Shares Beneficially Owned by the Technology Persons.
Notwithstanding the foregoing, after the date hereof if the Technology Persons
cease to be the Beneficial Owner of the Designated Percentage of the Common
Shares of the Company then outstanding, then this Section 1(a)(iii) shall be of
no further force or effect, except the immediately preceding sentence shall
continue to apply.

               (b) "AFFILIATE" and "ASSOCIATE" shall have the following
meanings:

                      (i) An "AFFILIATE" of, or a Person "AFFILIATED" with, a
specified Person, is a Person that directly, or indirectly through one or more
intermediaries, controls, or is controlled by, or is under common control with,
the Person specified. For this purpose, "control" (including the terms
"CONTROLLING," "CONTROLLED by" and "UNDER COMMON CONTROL WITH") means the
possession, direct or indirect, of the power to direct or cause the direction of
the management and policies of a Person, whether through the ownership of voting
securities, by contract or otherwise;

                      (ii) The term "ASSOCIATE" used to indicate a relationship
with any Person shall mean (A) any corporation or organization (other than the
Company or a majority-owned subsidiary of the Company) of which such Person is
an officer or partner or is, directly or indirectly, the Beneficial Owner of 10%
or more of any class of equity securities, (B) any trust or other estate in
which such Person has a substantial beneficial interest or as to which such
Person serves as trustee or in a similar fiduciary capacity, and (C) any
relative or spouse of such Person, or any relative of such spouse, who has the
same home as such Person or who is a director or officer of the Company or any
of its parents or Subsidiaries.

               (c) A Person shall be deemed the "BENEFICIAL OWNER" of and shall
be deemed to "BENEFICIALLY OWN" any securities:

                      (i) which such Person owns, directly or indirectly;



                                       2
<PAGE>   6

                      (ii) which such Person has (A) the right to acquire
(whether such right is exercisable immediately or only after the passage of
time) pursuant to any agreement, arrangement or understanding (other than
customary agreements with and between underwriters and selling group members
with respect to a bona fide public offering of securities), written or
otherwise, or upon the exercise of conversion rights, exchange rights, rights
(other than the Rights), warrants or options, or otherwise; provided, however,
that a Person shall not be deemed to be the Beneficial Owner of, or to
beneficially own, securities tendered pursuant to a tender or exchange offer
made by or on behalf of such Person until such tendered securities are accepted
for purchase or exchange; or (B) the right to vote pursuant to any agreement,
arrangement or understanding; provided, however, that a Person shall not be
deemed the Beneficial Owner of, or to beneficially own, any security if the
agreement, arrangement or understanding to vote such security (1) arises solely
from a revocable proxy or consent given to such Person in response to a public
proxy or consent solicitation made pursuant to, and in accordance with, the
applicable rules and regulations promulgated under the Exchange Act and (2) is
not also then reportable on Schedule 13D under the Exchange Act (or any
comparable or successor report); or

                      (iii) which are beneficially owned, directly or
indirectly, by any other Person with which such Person has any agreement,
arrangement or understanding (other than customary agreements with and between
underwriters and selling group members with respect to a bona fide public
offering of securities), written or otherwise, for the purpose of acquiring,
holding, voting (except to the extent contemplated by the proviso to Section
1(c)(ii)(B)) or disposing of any securities of the Company.

                      Notwithstanding anything in this definition of Beneficial
Ownership to the contrary, (A) the phrase "THEN OUTSTANDING," when used with
reference to a Person's Beneficial Ownership of securities of the Company, shall
mean the number of such securities then issued and outstanding together with the
number of such securities not then actually issued and outstanding which such
Person would be deemed to own beneficially hereunder, and (B) a Person who is a
director or officer of the Company or who is an Affiliate or Associate of a
director or officer of the Company (each, an "EXEMPTED PERSON") shall not be
deemed to "beneficially own" Common Shares held by another Exempted Person
solely by reason of any agreement, arrangement or understanding, written or
otherwise, entered into in opposition to a transaction that, at the time such
agreement, arrangement or understanding was entered into, has not been approved
or recommended by the Board of Directors to the stockholders of the Company.

               (d) "BUSINESS DAY" shall mean any day other than a Saturday, a
Sunday, or a day on which banking institutions in the Commonwealth of
Massachusetts are authorized or obligated by law or executive order to close.

               (e) "CLOSE OF BUSINESS" on any given date shall mean 5:00 p.m.,
Massachusetts Time, on such date; provided, however, that if such date is not a
Business Day it shall mean 5:00 p.m., Massachusetts Time, on the next succeeding
Business Day.

               (f) "COMMON SHARES" when used with reference to the Company shall
mean the shares of common stock, par value $0.001 per share, of the Company.
"Common Shares" when used with reference to any Person other than the Company
shall mean the capital stock (or



                                       3
<PAGE>   7

equity interest) with the greatest voting power of such other Person or, if such
other Person is a Subsidiary of another Person, the Person or Persons which
ultimately control such first-mentioned Person.

               (g) "DESIGNATED PERCENTAGE" shall have the meaning set forth in
Section 1(a) hereof.

               (h) "DISTRIBUTION DATE" shall have the meaning set forth in
Section 3 hereof.

               (i) "EXCHANGE ACT" shall mean the Securities Exchange Act of
1934, as amended.

               (j) "FINAL EXPIRATION DATE" shall have the meaning set forth in
Section 7(a) hereof.

               (k) "PERSON" shall mean any individual, firm, corporation,
partnership, limited partnership, business trust, unincorporated association or
other entity, and shall include any successor (by merger or otherwise) of such
entity.

               (l) "PURCHASE PRICE" shall have the meaning set forth in Section
7(b) hereof.

               (m) "PREFERRED SHARES" shall mean shares of Series A Junior
Participating Preferred Stock, par value $0.001 per share, of the Company having
the rights and preferences set forth in the Certificate of Designations attached
to this Agreement as Exhibit A.

               (n) "REDEMPTION DATE" shall have the meaning set forth in Section
7(a) hereof.

               (o) "SHARES ACQUISITION DATE" shall mean the earlier of the date
of (i) the public announcement by the Company or an Acquiring Person that an
Acquiring Person has become such or (ii) the public disclosure of facts by the
Company or an Acquiring Person indicating that an Acquiring Person has become
such.

               (p) "SUBSIDIARY" of any Person shall mean any Person of which a
majority of the voting power of the voting equity securities or equity interest
is owned, directly or indirectly, by such Person.

               (q) A "SUCCESSOR" shall mean the estate or legal representative
of a deceased individual, the beneficiary of a deceased individual's estate, a
trust created by a deceased individual as grantor, or the beneficiary of a trust
created by a deceased individual as grantor.

        SECTION 2. APPOINTMENT OF RIGHTS AGENT. The Company hereby appoints the
Rights Agent to act as agent for the Company and the holders of the Rights (who,
in accordance with Section 3 hereof, shall prior to the Distribution Date also
be the holders of the Common Shares) in accordance with the terms and conditions
hereof, and the Rights Agent hereby accepts such appointment. The Company may
from time to time appoint such co-Rights Agents as it may deem necessary or
desirable upon ten (10) days' prior written notice to the Rights Agent. The
Rights Agent shall have no duty to supervise, and in no event shall be liable
for, the acts or



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omissions of any such co-Rights Agent.

        SECTION 3. ISSUE OF RIGHT CERTIFICATES.

               (a) Until the earlier of (i) the tenth day after the Shares
Acquisition Date or (ii) the tenth Business Day (or such later date as may be
determined by action of the Board of Directors of the Company prior to such time
as any Person becomes an Acquiring Person) after the first public announcement
of the intention of any Person (other than the Company, any Subsidiary of the
Company, any employee benefit plan of the Company or of any Subsidiary of the
Company or any entity holding Common Shares for or pursuant to the terms of any
such plan) to commence a tender or exchange offer the consummation of which
would result in any such Person becoming an Acquiring Person (including any such
date which is after the date of this Agreement and prior to the issuance of the
Rights; the earlier of such dates being herein referred to as the "DISTRIBUTION
DATE"); (x) the Rights will be evidenced (subject to the provisions of Section
3(b) hereof) by the certificates for Common Shares registered in the names of
the holders thereof (which certificates shall also be deemed to be Right
Certificates) and not by separate Right Certificates, and (y) the right to
receive Right Certificates will be transferable only in connection with the
transfer of Common Shares. As soon as practicable after the Distribution Date,
the Company will prepare and execute, the Rights Agent will countersign, and the
Company will send or cause to be sent (and the Rights Agent will, if requested,
send) by first-class, insured, postage-prepaid mail, to each record holder of
Common Shares as of the Close of Business on the Distribution Date, at the
address of such holder shown on the records of the Company, a Right Certificate,
in substantially the form of Exhibit B hereto (a "RIGHT CERTIFICATE"),
evidencing one Right for each Common Share so held. As of the Distribution Date,
the Rights will be evidenced solely by such Right Certificates.

               (b) On the Record Date, or as soon as practicable thereafter, the
Company will send a copy of a Summary of Rights to Purchase Preferred Shares, in
substantially the form of Exhibit C hereto (the "SUMMARY OF RIGHTS"), by
first-class, postage-prepaid mail, to each record holder of Common Shares as of
the Close of Business on the Record Date, at the address of such holder shown on
the records of the Company. With respect to certificates for Common Shares
outstanding as of the Record Date, until the Distribution Date, the Rights will
be evidenced by such certificates registered in the names of the holders thereof
together with a copy of the Summary of Rights attached thereto. Until the
Distribution Date (or the earlier of the Redemption Date or the Final Expiration
Date), the surrender for transfer of any certificate for Common Shares
outstanding on the Record Date, with or without a copy of the Summary of Rights
attached thereto, shall also constitute the transfer of the Rights associated
with the Common Shares represented thereby.

               (c) Certificates for Common Shares which become outstanding
(including, without limitation, reacquired Common Shares referred to in the last
sentence of this paragraph (c)) after the Record Date but prior to the earliest
of the Distribution Date, the Redemption Date or the Final Expiration Date shall
have impressed on, printed on, written on or otherwise affixed to them the
following legend:

               THIS CERTIFICATE ALSO EVIDENCES AND ENTITLES THE HOLDER HEREOF
               TO CERTAIN RIGHTS (THE



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<PAGE>   9

               "RIGHTS") AS SET FORTH IN A RIGHTS AGREEMENT BETWEEN LARGE SCALE
               BIOLOGY CORPORATION (THE "COMPANY") AND EQUISERVE TRUST COMPANY,
               N.A., DATED AS OF APRIL 27, 2001, AS SUCH MAY SUBSEQUENTLY BE
               AMENDED (THE "RIGHTS AGREEMENT"), THE TERMS OF WHICH ARE HEREBY
               INCORPORATED HEREIN BY REFERENCE AND A COPY OF WHICH IS ON FILE
               AT THE PRINCIPAL EXECUTIVE OFFICES OF THE COMPANY. UNDER CERTAIN
               CIRCUMSTANCES, AS SET FORTH IN THE RIGHTS AGREEMENT, SUCH RIGHTS
               WILL BE EVIDENCED BY SEPARATE CERTIFICATES AND WILL NO LONGER BE
               EVIDENCED BY THIS CERTIFICATE. THE COMPANY WILL MAIL TO THE
               HOLDER OF THIS CERTIFICATE A COPY OF THE RIGHTS AGREEMENT WITHOUT
               CHARGE AFTER RECEIPT OF A WRITTEN REQUEST THEREFOR. AS DESCRIBED
               IN SECTION 11(a)(ii) OF THE RIGHTS AGREEMENT, RIGHTS BENEFICIALLY
               OWNED BY ANY PERSON WHO BECOMES AN ACQUIRING PERSON (AS DEFINED
               IN THE RIGHTS AGREEMENT) AND CERTAIN OTHER PERSONS SHALL BECOME
               NULL AND VOID.

With respect to such certificates containing the foregoing legend, until the
Distribution Date, the Rights associated with the Common Shares represented by
such certificates shall be evidenced by such certificates alone, and the
surrender for transfer of any such certificate shall also constitute the
transfer of the Rights associated with the Common Shares represented thereby. In
the event that the Company purchases or acquires any Common Shares after the
Record Date but prior to the Distribution Date, any Rights associated with such
Common Shares shall be deemed cancelled and retired so that the Company shall
not be entitled to exercise any Rights associated with the Common Shares which
are no longer outstanding.

        SECTION 4. FORM OF RIGHT CERTIFICATES. The Right Certificates (and the
forms of election to purchase Preferred Shares and of assignment to be printed
on the reverse thereof) shall be substantially the same as Exhibit B hereto and
may have such marks of identification or designation and such legends, summaries
or endorsements printed thereon as the Company may deem appropriate and as are
not inconsistent with the provisions of this Agreement, or as may be required to
comply with any applicable law or with any rule or regulation made pursuant
thereto or with any rule or regulation of any stock exchange on which the Rights
may from time to time be listed, or to conform to usage. Subject to the other
provisions of this Agreement, the Right Certificates shall entitle the holders
thereof to purchase such number of one one-hundredth of a Preferred Share as
shall be set forth therein at the Purchase Price, but the number of such one
one-hundredths of a Preferred Share and the Purchase Price shall be subject to
adjustment as provided herein.

        SECTION 5. COUNTERSIGNATURE AND REGISTRATION. The Right Certificates
shall be executed on behalf of the Company by its Chairman of the Board, its
Chief Executive Officer, its



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<PAGE>   10

President, any of its Vice Presidents, or its Treasurer, either manually or by
facsimile signature, shall have affixed thereto the Company's seal or a
facsimile thereof, and shall be attested by the Secretary or any Assistant
Secretary of the Company, either manually or by facsimile signature. The Right
Certificates shall be manually countersigned by the Rights Agent (unless
applicable exchange rules and law permit facsimile signature, in which case the
Rights Agent signature may be by facsimile) and shall not be valid for any
purpose unless countersigned. In case any officer of the Company who shall have
signed any of the Right Certificates shall cease to be such officer of the
Company before countersignature by the Rights Agent and issuance and delivery by
the Company, such Right Certificates, nevertheless, may be countersigned by the
Rights Agent and issued and delivered by the Company with the same force and
effect as though the person who signed such Right Certificates had not ceased to
be such officer of the Company; and any Right Certificate may be signed on
behalf of the Company by any person who, at the actual date of the execution of
such Right Certificate, shall be a proper officer of the Company to sign such
Right Certificate, although at the date of the execution of this Rights
Agreement any such person was not such an officer.

        Following the Distribution Date, the Rights Agent will keep or cause to
be kept, at its principal office, books for registration and transfer of the
Right Certificates issued hereunder. Such books shall show the names and
addresses of the respective holders of the Right Certificates, the number of
Rights evidenced on its face by each of the Right Certificates and the date of
each of the Right Certificates.

        SECTION 6. TRANSFER, SPLIT UP, COMBINATION AND EXCHANGE OF RIGHT
CERTIFICATES; MUTILATED, DESTROYED, LOST OR STOLEN RIGHT CERTIFICATES. Subject
to the provisions of Section 14 hereof, at any time after the Close of Business
on the Distribution Date, and at or prior to the Close of Business on the
earlier of the Redemption Date or the Final Expiration Date, any Right
Certificate or Right Certificates (other than Right Certificates representing
Rights that have become void pursuant to Section 11(a)(ii) hereof or that have
been exchanged pursuant to Section 24 hereof) may be transferred, split up,
combined or exchanged for another Right Certificate or Right Certificates,
entitling the registered holder to purchase a like number of one one-hundredths
of a Preferred Share as the Right Certificate or Right Certificates surrendered
then entitled such holder to purchase. Any registered holder desiring to
transfer, split up, combine or exchange any Right Certificate or Right
Certificates shall make such request in writing delivered to the Rights Agent,
and shall surrender the Right Certificate or Right Certificates to be
transferred, split up, combined or exchanged at the principal office of the
Rights Agent. Thereupon the Company shall execute and the Rights Agent shall
countersign and deliver to the person entitled thereto a Right Certificate or
Right Certificates, as the case may be, as so requested. The Company may require
payment of a sum sufficient for any tax or governmental charge that may be
imposed in connection with any transfer, split up, combination or exchange of
Right Certificates. The Rights Agent shall have no duty or obligation under this
Section unless and until it is satisfied that all such taxes and/or charges have
been paid.

        Upon receipt by the Company and the Rights Agent of evidence reasonably
satisfactory to them of the loss, theft, destruction or mutilation of a Right
Certificate, and, in case of loss, theft or destruction, of indemnity or
security reasonably satisfactory to them, and, at the Company's request,
reimbursement to the Company and the Rights Agent of all reasonable expenses
incidental thereto, and upon surrender to the Rights Agent and cancellation of
the Right



                                       7
<PAGE>   11

Certificate if mutilated, the Company will make and deliver a new Right
Certificate of like tenor to the Rights Agent for delivery to the registered
holder in lieu of the Right Certificate so lost, stolen, destroyed or mutilated.

        SECTION 7. EXERCISE OF RIGHTS; PURCHASE PRICE; EXPIRATION DATE OF
RIGHTS.

               (a) The registered holder of any Right Certificate may exercise
the Rights evidenced thereby (except as otherwise provided herein) in whole or
in part at any time after the Distribution Date upon surrender of the Right
Certificate, with the form of election to purchase on the reverse side thereof
duly executed, to the Rights Agent at the principal office of the Rights Agent,
together with payment of the Purchase Price for each one one-hundredth of a
Preferred Share as to which the Rights are exercised, at or prior to the
earliest of (i) the Close of Business on the tenth anniversary of the date
hereof (the "FINAL EXPIRATION DATE"), (ii) the time at which the Rights are
redeemed as provided in Section 23 hereof (the "REDEMPTION DATE"), or (iii) the
time at which such Rights are exchanged as provided in Section 24 hereof.

               (b) The purchase price for each one one-hundredth of a Preferred
Share pursuant to the exercise of a Right (the "PURCHASE PRICE") shall initially
be $45.00, shall be subject to adjustment from time to time as provided in
Sections 11 and 13 hereof and shall be payable in lawful money of the United
States of America in accordance with paragraph (c) below.

               (c) Upon receipt of a Right Certificate representing exercisable
Rights, with the form of election to purchase and certificate duly executed,
accompanied by payment of the Purchase Price for the shares to be purchased and
an amount equal to any applicable transfer tax required to be paid by the holder
of such Right Certificate in accordance with Section 9 hereof by certified
check, cashier's check or money order payable to the order of the Company, the
Rights Agent shall thereupon promptly (i) (A) requisition from any transfer
agent of the Preferred Shares certificates for the number of one-one hundredths
of a Preferred Share to be purchased and the Company hereby irrevocably
authorizes its transfer agent to comply with all such requests, or (B)
requisition from any depositary agent for the Preferred Shares depositary
receipts representing such number of one one-hundredths of a Preferred Share as
are to be purchased (in which case certificates for the Preferred Shares
represented by such receipts shall be deposited by the transfer agent with the
depositary agent) and the Company hereby directs the depositary agent to comply
with such request, (ii) when appropriate, requisition from the Company the
amount of cash to be paid in lieu of issuance of fractional Preferred Shares in
accordance with Section 14 hereof, (iii) after receipt of such certificates or
depositary receipts, cause the same to be delivered to or upon the order of the
registered holder of such Right Certificate, registered in such name or names as
may be designated by such holder and (iv) when appropriate, after receipt,
deliver such cash to or upon the order of the registered holder of such Right
Certificate.

               (d) In case the registered holder of any Right Certificate shall
exercise less than all the Rights evidenced thereby, a new Right Certificate
evidencing Rights equivalent to the Rights remaining unexercised shall be issued
by the Rights Agent to the registered holder of such Right Certificate or to
such holder's duly authorized assigns, subject to the provisions of Section 14
hereof.



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<PAGE>   12

               (e) The Company covenants and agrees that it will cause to be
reserved and kept available, out of its authorized and unissued Preferred Shares
or any Preferred Shares held in its treasury, the number of Preferred Shares
that will be sufficient to permit the exercise in full of all outstanding Rights
in accordance with this Section 7.

               (f) Notwithstanding anything in this Agreement to the contrary,
neither the Rights Agent nor the Company shall be obligated to undertake any
action with respect to a registered holder upon the occurrence of any purported
exercise as set forth in this Section 7 unless such registered holder shall have
(i) completed and signed the certificate following the form of election to
purchase set forth on the reverse side of the Right Certificate surrendered for
such exercise and (ii) provided such additional evidence of the identity of the
Beneficial Owner (or former Beneficial Owner) or Affiliates or Associates
thereof as the Company shall reasonably request.

        SECTION 8. CANCELLATION AND DESTRUCTION OF RIGHT CERTIFICATES. All Right
Certificates surrendered for the purpose of exercise, transfer, split up,
combination or exchange shall, if surrendered to the Company or to any of its
agents, be delivered to the Rights Agent for cancellation or in cancelled form,
or, if surrendered to the Rights Agent, shall be cancelled by it, and no Right
Certificates shall be issued in lieu thereof except as expressly permitted by
any of the provisions of this Rights Agreement. The Company shall deliver to the
Rights Agent for cancellation and retirement, and the Rights Agent shall so
cancel and retire, any other Right Certificate purchased or acquired by the
Company otherwise than upon the exercise thereof. The Rights Agent shall deliver
all cancelled Right Certificates to the Company, or shall, at the written
request of the Company, destroy such cancelled Right Certificates, and in such
case shall deliver a certificate of destruction thereof to the Company.

        SECTION 9. STATUS AND AVAILABILITY OF PREFERRED SHARES. The Company
covenants and agrees that it will take all such action as may be necessary to
ensure that all Preferred Shares delivered upon exercise of Rights shall, at the
time of delivery of the certificates for such Preferred Shares (subject to
payment of the Purchase Price), be duly and validly authorized and issued and
fully paid and non-assessable shares.

        The Company further covenants and agrees that it will pay when due and
payable any and all federal and state transfer taxes and charges which may be
payable in respect of the issuance or delivery of the Right Certificates or of
any Preferred Shares upon the exercise of Rights. The Company shall not,
however, be required to pay any transfer tax which may be payable in respect of
any transfer or delivery of Right Certificates to a person other than, or the
issuance or delivery of certificates or depositary receipts for the Preferred
Shares in a name other than that of, the registered holder of the Right
Certificate evidencing Rights surrendered for exercise or to issue or to deliver
any certificates or depositary receipts for Preferred Shares upon the exercise
of any Rights until any such tax shall have been paid (any such tax being
payable by the holder of such Right Certificate at the time of surrender) or
until it has been established to the Company's reasonable satisfaction that no
such tax is due.

        SECTION 10. PREFERRED SHARES RECORD DATE. Each person in whose name any
certificate for Preferred Shares is issued upon the exercise of Rights shall for
all purposes be deemed to have become the holder of record of the Preferred
Shares represented thereby on, and



                                       9
<PAGE>   13

such certificate shall be dated, the date upon which the Right Certificate
evidencing such Rights was duly surrendered and payment of the Purchase Price
(and any applicable transfer taxes) was made. Prior to the exercise of the
Rights evidenced thereby, the holder of a Right Certificate shall not be
entitled to any rights of a holder of Preferred Shares for which the Rights
shall be exercisable, including, without limitation, the right to vote, to
receive dividends or other distributions or to exercise any preemptive rights,
and shall not be entitled to receive any notice of any proceedings of the
Company, except as provided herein.

        SECTION 11. ADJUSTMENT OF PURCHASE PRICE, NUMBER OF SHARES OR NUMBER OF
RIGHTS. The Purchase Price, the number of Preferred Shares covered by each Right
and the number of Rights outstanding are subject to adjustment from time to time
as provided in this Section 11.

               (a) (i) In the event the Company shall at any time after the date
of this Agreement (A) declare a dividend on the Preferred Shares payable in
Preferred Shares, (B) subdivide the outstanding Preferred Shares, (C) combine
the outstanding Preferred Shares into a smaller number of Preferred Shares or
(D) issue any shares of its capital stock in a reclassification of the Preferred
Shares (including any such reclassification in connection with a consolidation
or merger in which the Company is the continuing or surviving corporation),
except as otherwise provided in this Section 11(a), the Purchase Price in effect
at the time of the record date for such dividend or of the effective date of
such subdivision, combination or reclassification, and the number and kind of
shares of capital stock issuable on such date, shall be proportionately adjusted
so that the holder of any Right exercised after such time shall be entitled to
receive the aggregate number and kind of shares of capital stock which, if such
Right had been exercised immediately prior to such date, such holder would have
owned upon such exercise and been entitled to receive by virtue of such
dividend, subdivision, combination or reclassification; provided, however, that
in no event shall the consideration to be paid upon the exercise of one Right be
less than the aggregate par value of the shares of capital stock of the Company
issuable upon exercise of one Right.

                   (ii) Subject to the last paragraph of this subparagraph
(ii) and to Section 24 of this Agreement, in the event that any Person shall
become an Acquiring Person, unless the event causing the Designated Percentage
threshold to be crossed and the Person to thereby become an Acquiring Person is
a transaction set forth in Section 13 hereof, each holder of a Right shall
thereafter have a right to receive, upon exercise thereof at a price equal to
the then current Purchase Price multiplied by the number of one one-hundredths
of a Preferred Share for which a Right is then exercisable, in accordance with
the terms of this Agreement and in lieu of Preferred Shares, such number of
Common Shares of the Company as shall equal the result obtained by (x)
multiplying the then current Purchase Price by the number of one one-hundredths
of a Preferred Share for which a Right is then exercisable and dividing that
product by (y) 50% of the then current per share market price of the Company's
Common Shares (determined pursuant to Section 11(d) hereof) on the date such
Person became an Acquiring Person.

                      From and after the occurrence of any Person becoming an
Acquiring Person, any Rights that are or were acquired or beneficially owned by
such Acquiring Person (or any Associate or Affiliate of such Acquiring Person)
shall be void and any holder of such Rights shall thereafter have no right to
exercise such Rights under any provision of this



                                       10
<PAGE>   14

Agreement. No Right Certificate shall be issued pursuant to Section 3 that
represents Rights beneficially owned by an Acquiring Person whose Rights would
be void pursuant to the preceding sentence or any Associate or Affiliate
thereof; no Right Certificate shall be issued at any time upon the transfer of
any Rights to an Acquiring Person whose Rights would be void pursuant to the
preceding sentence or any Associate or Affiliate thereof or to any nominee of
such Acquiring Person, Associate or Affiliate; and any Right Certificate
delivered to the Rights Agent for transfer to an Acquiring Person whose Rights
would be void pursuant to the preceding sentence or any Associate or Affiliate
thereof shall be canceled. This paragraph shall apply not only to an initial
Acquiring Person, and its Affiliates and Associates, but also to subsequent
Acquiring Persons, and their Affiliates and Associates.

                      (iii) In the event that the number of Common Shares which
are authorized by the Company's certificate of incorporation and not outstanding
or subscribed for, or reserved or otherwise committed for issuance for purposes
other than upon exercise of the Rights, is not sufficient to permit the holder
of each Right to purchase the number of Common Shares to which such holder would
be entitled upon the exercise in full of the Rights in accordance with the
foregoing subparagraph (ii) of paragraph (a) of this Section 11, the Company
shall: (A) determine the excess of (1) the value of the Common Shares issuable
upon the exercise of a Right (calculated as provided in the last sentence of
this subparagraph (iii)) pursuant to Section 11(a)(ii) hereof (the "CURRENT
VALUE") over (2) the Purchase Price (such excess, the "SPREAD"), and (B) with
respect to each Right, make adequate provision to substitute for such Common
Shares, upon payment of the applicable Purchase Price, (1) cash, (2) a reduction
in the Purchase Price, (3) Common Shares or other equity securities of the
Company (including, without limitation, shares, or units of shares, of preferred
stock which the Board of Directors of the Company has determined to have the
same value as shares of common stock (such equity securities, "COMMON STOCK
EQUIVALENTS")), (4) debt securities of the Company, (5) other assets, or (6) any
combination of the foregoing, having an aggregate value equal to the Current
Value, where such aggregate value has been determined by the Board of Directors
of the Company in good faith; provided, however, if the Company shall not have
made adequate provision to deliver value pursuant to clause (B) above within
thirty (30) days following the first occurrence of an event triggering the
rights to purchase Common Shares described in Section 11(a)(ii) (the "SECTION
11(a)(ii) TRIGGER DATE"), then the Company shall be obligated to deliver, upon
the surrender for exercise of a Right without requiring payment of the Purchase
Price, shares of common stock (to the extent available) and then, if necessary,
cash, which shares and cash have an aggregate value equal to the Spread. If the
Board of Directors of the Company shall determine in good faith that it is
likely that sufficient additional shares of common stock could be authorized for
issuance upon exercise in full of the Rights, the thirty (30) day period set
forth above may be extended to the extent necessary, but not more than ninety
(90) days after the Section 11(a)(ii) Trigger Date, in order that the Company
may seek stockholder approval for the authorization of such additional shares
(such period, as it may be extended, the "SUBSTITUTION PERIOD"). To the extent
that the Company determines that some action need be taken pursuant to the first
and/or second sentences of this Section 11(a)(iii), the Company (x) shall
provide, subject to Section 7(f) hereof, that such action shall apply uniformly
to all outstanding Rights, and (y) may suspend the exercisability of the Rights
until the expiration of the Substitution Period in order to seek any
authorization of additional shares and/or to decide the appropriate form of
distribution to be made pursuant to such first sentence and to determine the
value thereof. In the event of any such suspension, the Company shall make a
public



                                       11
<PAGE>   15

announcement, and shall deliver to the Rights Agent a statement, stating that
the exercisability of the Rights has been temporarily suspended. At such time as
the suspension is no longer in effect, the Company shall make another public
announcement, and deliver to the Rights Agent a statement, so stating. For
purposes of this Section 11(a)(iii), the value of the Common Shares shall be the
current per share market price (as determined pursuant to Section 11(d)(i)
hereof) of the Common Shares on the Section 11(a)(ii) Trigger Date and the value
of any "common stock equivalent" shall be deemed to have the same value as the
Common Shares on such date.

               (b) In case the Company shall fix a record date for the issuance
of rights, options or warrants to all holders of Preferred Shares entitling them
to subscribe for or purchase Preferred Shares (or shares having the same rights,
privileges and preferences as the Preferred Shares ("EQUIVALENT PREFERRED
SHARES")) or securities convertible into Preferred Shares or equivalent
preferred shares at a price per Preferred Share or equivalent preferred share
(or having a conversion price per share, if a security convertible into
Preferred Shares or equivalent preferred shares) less than the then current per
share market price of the Preferred Shares (as defined in Section 11(d)) on such
record date, the Purchase Price to be in effect after such record date shall be
determined by multiplying the Purchase Price in effect immediately prior to such
record date by a fraction, the numerator of which shall be the number of
Preferred Shares outstanding on such record date plus the number of Preferred
Shares which the aggregate offering price of the total number of Preferred
Shares and/or equivalent preferred shares so to be offered (and/or the aggregate
initial conversion price of the convertible securities so to be offered) would
purchase at such current market price and the denominator of which shall be the
number of Preferred Shares outstanding on such record date plus the number of
additional Preferred Shares and/or equivalent preferred shares to be offered for
subscription or purchase (or into which the convertible securities so to be
offered are initially convertible); provided, however, that in no event shall
the consideration to be paid upon the exercise of one Right be less than the
aggregate par value of the shares of capital stock of the Company issuable upon
exercise of one Right. In case such subscription price may be paid in a
consideration part or all of which shall be in a form other than cash, the value
of such consideration shall be as determined in good faith by the Board of
Directors of the Company, whose determination shall be described in a statement
filed with the Rights Agent. Preferred Shares owned by or held for the account
of the Company shall not be deemed outstanding for the purpose of any such
computation. Such adjustment shall be made successively whenever such a record
date is fixed; and in the event that such rights, options or warrants are not so
issued, the Purchase Price shall be adjusted to be the Purchase Price which
would then be in effect if such record date had not been fixed.

               (c) In case the Company shall fix a record date for the making of
a distribution to all holders of the Preferred Shares (including any such
distribution made in connection with a consolidation or merger in which the
Company is the continuing or surviving corporation) of evidences of indebtedness
or assets (other than a regular quarterly cash dividend or a dividend payable in
Preferred Shares) or subscription rights or warrants (excluding those referred
to in Section 11(b) hereof), the Purchase Price to be in effect after such
record date shall be determined by multiplying the Purchase Price in effect
immediately prior to such record date by a fraction, the numerator of which
shall be the then current per share market price of the Preferred Shares on such
record date, less the fair market value (as determined in good faith by the
Board of Directors of the Company, whose determination shall be described in a
statement



                                       12
<PAGE>   16

filed with the Rights Agent) of the portion of the assets or evidences of
indebtedness so to be distributed or of such subscription rights or warrants
applicable to one Preferred Share and the denominator of which shall be such
current per share market price of the Preferred Shares; provided, however, that
in no event shall the consideration to be paid upon the exercise of one Right be
less than the aggregate par value of the shares of capital stock of the Company
to be issued upon exercise of one Right. Such adjustments shall be made
successively whenever such a record date is fixed; and in the event that such
distribution is not so made, the Purchase Price shall again be adjusted to be
the Purchase Price which would then be in effect if such record date had not
been fixed.

               (d) (i) For the purpose of any computation hereunder, the
"CURRENT PER SHARE MARKET PRICE" of any security (a "SECURITY" for the purpose
of this Section 11(d)(i)) on any date shall be deemed to be the average of the
daily closing prices per share of such Security for the 30 consecutive Trading
Days (as such term is hereinafter defined) immediately prior to such date;
provided, however, that in the event that the current per share market price of
the Security is determined during a period following the announcement by the
issuer of such Security of (A) a dividend or distribution on such Security
payable in shares of such Security or securities convertible into such shares,
or (B) any subdivision, combination or reclassification of such Security and
prior to the expiration of 30 Trading Days after the ex-dividend date for such
dividend or distribution, or the record date for such subdivision, combination
or reclassification, then, and in each such case, the current per share market
price shall be appropriately adjusted to reflect the current market price per
share equivalent of such Security. The closing price for each day shall be the
last sale price, regular way, or, in case no such sale takes place on such day,
the average of the closing bid and asked prices, regular way, in either case as
reported in the principal consolidated transaction reporting system with respect
to securities listed or admitted to trading on the New York Stock Exchange or,
if the Security is not listed or admitted to trading on the New York Stock
Exchange, as reported in the principal consolidated transaction reporting system
with respect to securities listed on the principal national securities exchange
on which the Security is listed or admitted to trading or, if the Security is
not listed or admitted to trading on any national securities exchange, the last
quoted price, or, if not so quoted, the average of the high bid and low asked
prices in the over-the-counter market, as reported by The Nasdaq Stock Market
("NASDAQ") or such other system then in use, or, if on any such date the
Security is not quoted by any such organization, the average of the closing bid
and asked prices as furnished by a professional market maker making a market in
the Security selected by the Board of Directors of the Company. The term
"TRADING DAY" shall mean a day on which the principal national securities
exchange on which the Security is listed or admitted to trading is open for the
transaction of business or, if the Security is not listed or admitted to trading
on any national securities exchange, a Business Day.

                      (i) For the purpose of any computation hereunder, the
"current per share market price" of the Preferred Shares shall be determined in
accordance with the method set forth in Section 11(d)(i). If the Preferred
Shares are not publicly traded, the "current per share market price" of the
Preferred Shares shall be conclusively deemed to be the current per share market
price of the Common Shares as determined pursuant to Section 11(d)(i)
(appropriately adjusted to reflect any stock split, stock dividend or similar
transaction occurring after the date hereof), multiplied by one hundred. If
neither the Common Shares nor the Preferred Shares are publicly held or so
listed or traded, "current per share market price" shall



                                       13
<PAGE>   17

mean the fair value per share as determined in good faith by the Board of
Directors of the Company, whose determination shall be described in a statement
filed with the Rights Agent.

               (e) No adjustment in the Purchase Price shall be required unless
such adjustment would require an increase or decrease of at least 1% in the
Purchase Price; provided, however, that any adjustments which by reason of this
Section 11(e) are not required to be made shall be carried forward and taken
into account in any subsequent adjustment. All calculations under this Section
11 shall be made to the nearest cent or to the nearest one one-millionth of a
Preferred Share or one one-thousandth of any other share or security as the case
may be. Notwithstanding the first sentence of this Section 11(e), any adjustment
required by this Section 11 shall be made no later than three years from the
date of the transaction which requires such adjustment.

               (f) If as a result of an adjustment made pursuant to Section
11(a) hereof, the holder of any Right thereafter exercised shall become entitled
to receive any shares of capital stock of the Company other than Preferred
Shares, the number of such other shares so receivable upon exercise of any Right
shall thereafter be subject to adjustment from time to time in a manner and on
terms as nearly equivalent as practicable to the provisions with respect to the
Preferred Shares contained in Section 11(a) through (c), inclusive, and the
provisions of Sections 7, 9, 10 and 13 with respect to the Preferred Shares
shall apply on like terms to any such other shares.

               (g) All Rights originally issued by the Company subsequent to any
adjustment made to the Purchase Price hereunder shall evidence the right to
purchase, at the adjusted Purchase Price, the number of one one-hundredths of a
Preferred Share purchasable from time to time hereunder upon exercise of the
Rights, all subject to further adjustment as provided herein.

               (h) Unless the Company shall have exercised its election as
provided in Section 11(i), upon each adjustment of the Purchase Price as a
result of the calculations made in Sections 11(b) and (c), each Right
outstanding immediately prior to the making of such adjustment shall thereafter
evidence the right to purchase, at the adjusted Purchase Price, that number of
one one-hundredths of a Preferred Share (calculated to the nearest one
one-millionth of a Preferred Share) obtained by (i) multiplying (x) the number
of one one-hundredths of a share covered by a Right immediately prior to this
adjustment by (y) the Purchase Price in effect immediately prior to such
adjustment of the Purchase Price and (ii) dividing the product so obtained by
the Purchase Price in effect immediately after such adjustment of the Purchase
Price.

               (i) The Company may elect on or after the date of any adjustment
of the Purchase Price to adjust the number of Rights in substitution for any
adjustment in the number of one one-hundredths of a Preferred Share purchasable
upon the exercise of a Right. Each of the Rights outstanding after such
adjustment of the number of Rights shall be exercisable for the number of one
one-hundredths of a Preferred Share for which a Right was exercisable
immediately prior to such adjustment. Each Right held of record prior to such
adjustment of the number of Rights shall become that number of Rights
(calculated to the nearest one one-thousandth) obtained by dividing the Purchase
Price in effect immediately prior to adjustment of the Purchase Price by the
Purchase Price in effect immediately after adjustment of the Purchase Price. The
Company shall make a public announcement of its election to adjust the number of



                                       14
<PAGE>   18

Rights, indicating the record date for the adjustment, and, if known at the
time, the amount of the adjustment to be made. This record date may be the date
on which the Purchase Price is adjusted or any day thereafter, but, if the Right
Certificates have been distributed, shall be at least 10 days later than the
date of the public announcement. If Right Certificates have been distributed,
upon each adjustment of the number of Rights pursuant to this Section 11(i), the
Company shall, as promptly as practicable, cause to be distributed to holders of
record of Right Certificates on such record date Right Certificates evidencing,
subject to Section 14 hereof, the additional Rights to which such holders shall
be entitled as a result of such adjustment, or, at the option of the Company,
shall cause to be distributed to such holders of record in substitution and
replacement for the Right Certificates held by such holders prior to the date of
adjustment, and upon surrender thereof, if required by the Company, new Right
Certificates evidencing all the Rights to which such holders shall be entitled
after such adjustment. Right Certificates to be so distributed shall be issued,
executed and countersigned in the manner provided for herein and shall be
registered in the names of the holders of record of Right Certificates on the
record date specified in the public announcement.

               (j) Irrespective of any adjustment or change in the Purchase
Price or the number of one one-hundredths of a Preferred Share issuable upon the
exercise of the Rights, the Right Certificates theretofore and thereafter issued
may continue to express the Purchase Price and the number of one one-hundredths
of a Preferred Share which were expressed in the initial Right Certificates
issued hereunder.

               (k) Before taking any action that would cause an adjustment
reducing the Purchase Price below one one-hundredth of the then par value of the
Preferred Shares issuable upon exercise of the Rights, the Company shall take
any corporate action which may, in the opinion of its counsel, be necessary in
order that the Company may validly and legally issue fully paid and
non-assessable Preferred Shares at such adjusted Purchase Price.

               (l) In any case in which this Section 11 shall require that an
adjustment in the Purchase Price be made effective as of a record date for a
specified event, the Company may elect to defer until the occurrence of such
event the issuing to the holder of any Right exercised after such record date of
the Preferred Shares and other capital stock or securities of the Company, if
any, issuable upon such exercise over and above the Preferred Shares and other
capital stock or securities of the Company, if any, issuable upon such exercise
on the basis of the Purchase Price in effect prior to such adjustment; provided,
however, that the Company shall deliver to such holder a due bill or other
appropriate instrument evidencing such holder's right to receive such additional
shares upon the occurrence of the event requiring such adjustment.

               (m) Anything in this Section 11 to the contrary notwithstanding,
the Company shall be entitled to make such reductions in the Purchase Price, in
addition to those adjustments expressly required by this Section 11, as and to
the extent that it in its sole discretion shall determine to be advisable in
order that any (i) consolidation or subdivision of the Preferred Shares, (ii)
issuance wholly for cash of Preferred Shares or securities which by their terms
are convertible into or exchangeable for Preferred Shares, (iii) dividends on
Preferred Shares payable in Preferred Shares or (iv) issuance of any rights,
options or warrants referred to hereinabove in Section 11(b), hereafter made by
the Company to holders of its Preferred Shares shall not be taxable to such
stockholders.



                                       15
<PAGE>   19

               (n) In the event that at any time after the date of this
Agreement and prior to the Distribution Date, the Company shall (i) declare or
pay any dividend on the Common Shares payable in Common Shares or (ii) effect a
subdivision, combination or consolidation of the Common Shares (by
reclassification or otherwise other than by payment of dividends in Common
Shares) into a greater or lesser number of Common Shares, then in any such case
(i) the number of one one-hundredths of a Preferred Share purchasable after such
event upon proper exercise of each Right shall be determined by multiplying the
number of one one-hundredths of a Preferred Share so purchasable immediately
prior to such event by a fraction, the numerator of which is the number of
Common Shares outstanding immediately before such event and the denominator of
which is the number of Common Shares outstanding immediately after such event,
and (ii) each Common Share outstanding immediately after such event shall have
issued with respect to it that number of Rights which each Common Share
outstanding immediately prior to such event had issued with respect to it. The
adjustments provided for in this Section 11(n) shall be made successively
whenever such a dividend is declared or paid or such a subdivision, combination
or consolidation is effected.

               (o) The Company covenants and agrees that, after the Distribution
Date, it will not, except as permitted by Sections 23, 24 and 27, take (or
permit any Subsidiary to take) any action if the purpose of such action is to,
or if at the time such action is taken it is reasonably foreseeable that such
action will, diminish substantially or eliminate the benefits intended to be
afforded by the Rights.

        SECTION 12. CERTIFICATE OF ADJUSTED PURCHASE PRICE OR NUMBER OF SHARES.
Whenever an adjustment is made as provided in Sections 11 and 13 hereof, the
Company shall promptly (a) prepare a certificate setting forth such adjustment,
and a brief statement of the facts accounting for such adjustment, (b) file with
the Rights Agent and with each transfer agent for the Common Shares or the
Preferred Shares a copy of such certificate and (c) mail a brief summary thereof
to each holder of a Right Certificate in accordance with Section 25 hereof.

        SECTION 13. CONSOLIDATION, MERGER OR SALE OR TRANSFER OF ASSETS OR
EARNING POWER. In the event that any Person shall become an Acquiring Person,
and, directly or indirectly, (a) the Company shall consolidate with, or merge
with and into, an Acquiring Person, or an Affiliate or Associate of an Acquiring
Person, (b) an Acquiring Person, or an Affiliate or Associate of an Acquiring
Person, shall consolidate with the Company, or merge with and into the Company
and the Company shall be the continuing or surviving corporation of such merger
and, in connection with such merger, all or part of the Common Shares shall be
changed into or exchanged for stock or other securities of any other Person (or
the Company) or cash or any other property, or (c) the Company shall sell or
otherwise transfer (or one or more of its Subsidiaries shall sell or otherwise
transfer), in one or more transactions, assets or earning power aggregating 50%
or more of the assets or earning power of the Company and its Subsidiaries
(taken as a whole) to an Acquiring Person, or an Affiliate or Associate of an
Acquiring Person, then, and in each such case, proper provision shall be made so
that (i) each holder of a Right (other than Rights which have become null and
void) shall thereafter have the right to receive, upon the exercise thereof at a
price equal to the then current Purchase Price multiplied by the number of one
one-hundredths of a Preferred Share for which a Right is then exercisable, in
accordance with the terms of this Agreement and in lieu of Preferred Shares,
such number of Common Shares of the Person in the transaction (including the
Company as successor thereto or



                                       16
<PAGE>   20

as the surviving corporation) who is issuing the consideration with the greatest
fair market value to the Company and its stockholders in connection with such
transaction (the "PRINCIPAL ISSUER") as shall equal the result obtained by (A)
multiplying the then current Purchase Price by the number of one one-hundredths
of a Preferred Share for which a Right is then exercisable and dividing that
product by (B) 50% of the then current per share market price of the Common
Shares of the Principal Issuer (determined pursuant to Section 11(d) hereof) on
the date of consummation of such consolidation, merger, sale or transfer; (ii)
the Principal Issuer shall be liable for, and shall assume, by virtue of such
consolidation, merger, sale or transfer, all the obligations and duties of the
Company pursuant to this Agreement; (iii) the term "Company" shall thereafter be
deemed to refer to the Principal Issuer; and (iv) the Principal Issuer shall
take such steps (including, but not limited to, the reservation of a sufficient
number of its Common Shares in accordance with Section 9 hereof) in connection
with such consummation as may be necessary to assure that the provisions hereof
shall thereafter be applicable, as nearly as reasonably may be, in relation to
the Common Shares thereafter deliverable upon the exercise of the Rights. The
Company covenants and agrees that it shall not consummate any such
consolidation, merger, sale or transfer unless prior thereto the Company and the
Principal Issuer shall have executed and delivered to the Rights Agent a
supplemental agreement so providing. The Company shall not enter into any
transaction of the kind referred to in this Section 13 if at the time of such
transaction there are any rights, warrants, instruments or securities
outstanding or any agreements or arrangements which, as a result of the
consummation of such transaction, would eliminate or substantially diminish the
benefits intended to be afforded by the Rights. The provisions of this Section
13 shall similarly apply to successive mergers or consolidations or sales or
other transfers.

        SECTION 14. FRACTIONAL RIGHTS AND FRACTIONAL SHARES.

               (a) The Company shall not be required to issue fractions of
Rights or to distribute Right Certificates which evidence fractional Rights. In
lieu of such fractional Rights, there shall be paid to the registered holders of
the Right Certificates with regard to which such fractional Rights would
otherwise be issuable, an amount in cash equal to the same fraction of the
current market value of a whole Right. For the purposes of this Section 14(a),
the current market value of a whole Right shall be the closing price of the
Rights for the Trading Day immediately prior to the date on which such
fractional Rights would have been otherwise issuable. The closing price for any
day shall be the last sale price, regular way, or, in case no such sale takes
place on such day, the average of the closing bid and asked prices, regular way,
in either case as reported in the principal consolidated transaction reporting
system with respect to securities listed or admitted to trading on the New York
Stock Exchange or, if the Rights are not listed or admitted to trading on the
New York Stock Exchange, as reported in the principal consolidated transaction
reporting system with respect to securities listed on the principal national
securities exchange on which the Rights are listed or admitted to trading or, if
the Rights are not listed or admitted to trading on any national securities
exchange, the last quoted price or, if not so quoted, the average of the high
bid and low asked prices in the over-the-counter market, as reported by Nasdaq
or such other system then in use or, if on any such date the Rights are not
quoted by any such organization, the average of the closing bid and asked prices
as furnished by a professional market maker making a market in the Rights
selected by the Board of Directors of the Company. If on any such date no such
market maker is making a market in the Rights, the



                                       17
<PAGE>   21

fair value of the Rights on such date as determined in good faith by the Board
of Directors of the Company shall be used.

               (b) The Company shall not be required to issue fractions of
Preferred Shares (other than fractions which are integral multiples of one
one-hundredth of a Preferred Share) upon exercise of the Rights or to distribute
certificates which evidence fractional Preferred Shares (other than fractions
which are integral multiples of one one-hundredth of a Preferred Share).
Fractions of Preferred Shares in integral multiples of one one-hundredth of a
Preferred Share may, at the election of the Company, be evidenced by depositary
receipts, pursuant to an appropriate agreement between the Company and a
depositary selected by it; provided, that such agreement shall provide that the
holders of such depositary receipts shall have all the rights, privileges and
preferences to which they are entitled as beneficial owners of the Preferred
Shares represented by such depositary receipts. In lieu of fractional Preferred
Shares that are not integral multiples of one one-hundredth of a Preferred
Share, the Company shall pay to the registered holders of Right Certificates at
the time such Rights are exercised as herein provided an amount in cash equal to
the same fractions of the current market value of one Preferred Share. For the
purposes of this Section 14(b), the current market value of a Preferred Share
shall be the closing price of a Preferred Share (as determined pursuant to the
second sentence of Section 11(d)(i) hereof) for the Trading Day immediately
prior to the date of such exercise.

               (c) The holder of a Right by the acceptance of the Right
expressly waives any right to receive fractional Rights or fractional shares
upon exercise of a Right (except as provided above).

        SECTION 15. RIGHTS OF ACTION. All rights of action in respect of this
Agreement, excepting the rights of action given to the Rights Agent under
Section 18 hereof, are vested in the respective registered holders of the Right
Certificates (and, prior to the Distribution Date, the registered holders of the
Common Shares); and any registered holder of any Right Certificate (or, prior to
the Distribution Date, of the Common Shares) may, without the consent of the
Rights Agent or of the holder of any other Right Certificate (or, prior to the
Distribution Date, of the Common Shares), in such holder's own behalf and for
such holder's own benefit, enforce, and may institute and maintain any suit,
action or proceeding against the Company to enforce, or otherwise act in respect
of, such holder's right to exercise the Rights evidenced by such Right
Certificate in the manner provided in such Right Certificate and in this
Agreement. Without limiting the foregoing or any remedies available to the
holders of Rights, it is specifically acknowledged that the holders of Rights
would not have an adequate remedy at law for any breach of this Agreement and
will be entitled to specific performance of the obligations under, and
injunctive relief against actual or threatened violations of the obligations of
any Person subject to, this Agreement.

        SECTION 16. AGREEMENT OF RIGHT HOLDERS. Every holder of a Right, by
accepting the same, consents and agrees with the Company and the Rights Agent
and with every other holder of a Right that:

               (a) prior to the Distribution Date, the Rights will be
transferable only in connection with the transfer of the Common Shares;



                                       18
<PAGE>   22

               (b) after the Distribution Date, the Right Certificates are
transferable only on the registry books maintained by the Rights Agent if
surrendered at the principal office of the Rights Agent, duly endorsed or
accompanied by a proper instrument of transfer; and

               (c) the Company and the Rights Agent may deem and treat the
person in whose name the Right Certificate (or, prior to the Distribution Date,
the associated Common Shares certificate) is registered as the absolute owner
thereof and of the Rights evidenced thereby (notwithstanding any notations of
ownership or writing on the Right Certificates or the associated Common Shares
certificate made by anyone other than the Company or the Rights Agent) for all
purposes whatsoever, and neither the Company nor the Rights Agent shall be
affected by any notice to the contrary.

        SECTION 17. RIGHT CERTIFICATE HOLDER NOT DEEMED A STOCKHOLDER. No
holder, as such, of any Right Certificate shall be entitled to vote, receive
dividends or be deemed for any purpose the holder of the Preferred Shares or any
other securities of the Company which may at any time be issuable on the
exercise of the Rights represented thereby nor shall anything contained herein
or in any Right Certificate be construed to confer upon the holder of any Right
Certificate, as such, any of the rights of a stockholder of the Company or any
right to vote for the election of directors or upon any matter submitted to
stockholders at any meeting thereof, or to give or withhold consent to any
corporate action, or to receive notice of meetings or other actions affecting
stockholders (except as provided in Section 25 hereof), or to receive dividends
or subscription rights, or otherwise, until the Right or Rights evidenced by
such Right Certificate shall have been exercised in accordance with the
provisions hereof.

        SECTION 18. COMPENSATION AND INDEMNITY OF THE RIGHTS AGENT. The Company
agrees to pay to the Rights Agent reasonable compensation for all services
rendered by it hereunder and, from time to time, on demand of the Rights Agent,
its reasonable expenses and counsel fees and other disbursements incurred in the
administration and execution of this Agreement and the exercise and performance
of its duties hereunder. The Company also agrees to indemnify the Rights Agent
(including employees, directors, officers and agents of the Rights Agent) for,
and to hold it harmless against, any loss, liability or expense, incurred
without gross negligence, bad faith or willful misconduct on the part of the
Rights Agent (including employees, directors, officers and agents of the Rights
Agent), for anything done or omitted by the Rights Agent (including employees,
directors, officers and agents of the Rights Agent) in connection with the
acceptance and administration of this Agreement.



                                       19
<PAGE>   23

        SECTION 19. MERGER OR CONSOLIDATION OR CHANGE OF NAME OF RIGHTS AGENT.
Any corporation into which the Rights Agent or any successor Rights Agent may be
merged or with which it may be consolidated, or any corporation resulting from
any merger or consolidation to which the Rights Agent or any successor Rights
Agent shall be a party, or any corporation succeeding to the stock transfer or
corporate trust business of the Rights Agent or any successor Rights Agent,
shall be the successor to the Rights Agent under this Agreement without the
execution or filing of any paper or any further act on the part of any of the
parties hereto, provided that such corporation would be eligible for appointment
as a successor Rights Agent under the provisions of Section 21 hereof. In case
at the time such successor Rights Agent shall succeed to the agency created by
this Agreement any of the Right Certificates shall have been countersigned but
not delivered, any such successor Rights Agent may adopt the countersignature of
the predecessor Rights Agent and deliver such Right Certificates so
countersigned; and in case at that time any of the Right Certificates shall not
have been countersigned, any successor Rights Agent may countersign such Right
Certificates either in the name of the predecessor Rights Agent or in the name
of the successor Rights Agent; and in all such cases such Right Certificates
shall have the full force provided in the Right Certificates and in this
Agreement.

        In case at any time the name of the Rights Agent shall be changed and at
such time any of the Right Certificates shall have been countersigned but not
delivered, the Rights Agent may adopt the countersignature under its prior name
and deliver Right Certificates so countersigned; and in case at that time any of
the Right Certificates shall not have been countersigned, the Rights Agent may
countersign such Right Certificates either in its prior name or in its changed
name; and in all such cases such Right Certificates shall have the full force
provided in the Right Certificates and in this Agreement.

        SECTION 20. RIGHTS AND DUTIES OF RIGHTS AGENT. The Rights Agent
undertakes the duties and obligations imposed by this Agreement upon the
following terms and conditions, by all of which the Company and the holders of
Right Certificates, by their acceptance thereof, shall be bound:

               (a) The Rights Agent may consult with legal counsel (who may be
legal counsel for the Company), and the opinion of such counsel shall be full
and complete authorization and protection to the Rights Agent as to any action
taken or omitted by it in good faith and in accordance with such opinion.

               (b) Whenever in the performance of its duties under this
Agreement the Rights Agent shall deem it necessary or desirable that any fact or
matter be proved or established by the Company prior to taking or suffering any
action hereunder, such fact or matter (unless other evidence in respect thereof
be herein specifically prescribed) may be deemed to be conclusively proved and
established by a certificate signed by any one of the Chairman of the Board, the
Chief Executive Officer, the President, any Vice President, the General Counsel,
the Treasurer or the Secretary of the Company and delivered to the Rights Agent;
and such certificate shall be full authorization to the Rights Agent for any
action taken or suffered in good faith by it under the provisions of this
Agreement in reliance upon such certificate.



                                       20
<PAGE>   24

               (c) The Rights Agent shall be protected and shall incur no
liability for any action taken, suffered or omitted by it in good faith unless a
court of competent jurisdiction determines that the Rights Agent's gross
negligence or willful misconduct was the primary cause of any loss to the
Company. The Rights Agent makes no representation or warranty with respect to
and is not responsible for the validity, value or availability of the Rights,
the Right Certificates or the Preferred Shares.

               (d) The Rights Agent shall be protected and shall incur no
liability for any action taken, suffered or omitted by it in connection with,
its administration of this Agreement in reliance upon any Right Certificate or
certificate for the Common Shares or for other securities of the Company,
instrument of assignment or transfer, power of attorney, endorsement, affidavit,
letter, notice, direction, consent, certificate, statement or other paper or
document believed by it to be genuine and to be signed, executed and, where
necessary, verified or acknowledged, by the proper Person or Persons, or
otherwise upon the advice of counsel as set forth in this Section 20.

               (e) The Rights Agent shall not be assumed to have knowledge of
and shall not be required to take note of or act upon any fact or circumstance
including, without limitation, the occurrence of facts or circumstances leading
to the Shares Acquisition Date or the Distribution Date, facts or circumstances
relating to whether any Person may be an Affiliate or an Associate of any other
Person, facts or circumstances relevant to an adjustment to the Purchase Price,
facts or circumstances relevant to events described in Section 13 (mergers,
etc.), Section 23 (redemption) and Section 24 (exchange) which may be relevant
to performance by the rights Agent under this Agreement unless the Company has
provided written notice thereof to the Rights Agent; and the Company agrees that
it will (i) promptly notify the Rights Agent in writing of the occurrence of the
Shares Acquisition Date (including the identity of the Acquiring Person and the
date on which the Shares Acquisition Date occurred), the Distribution Date, the
Redemption Date, and of any events described in Section 13 (merger), and (ii)
promptly provide the Rights Agent with such other information as the Rights
Agent may reasonably request in connection with the performance of its duties
under this Agreement.

               (f) Anything in this Agreement to the contrary notwithstanding,
in no event shall the Rights Agent be liable for special, indirect or
consequential damage or loss of any kind whatsoever (including but not limited
to lost profits), even if the Rights Agent has been advised of the likelihood of
such loss or damage and regardless of the form of action, provided the Rights
Agent has acted in good faith under this Agreement.

               (g) The Company agrees that it will perform, execute, acknowledge
and deliver or cause to be performed, executed, acknowledged and delivered all
such further and other acts, instruments and assurances as may reasonably be
required by the Rights Agent for the carrying out or performing by the Rights
Agent of the provisions of this Agreement.

               (h) The Rights Agent is hereby authorized and directed to accept
instructions with respect to the performance of its duties hereunder from any
one of the Chairman of the Board, the Chief Executive Officer, the President,
any Vice President, the General Counsel, the Secretary or the Treasurer of the
Company, and to apply to such officers for advice or instructions in connection
with its duties, and it shall not be liable for any action taken or suffered by
it in good faith in accordance with instructions of any such officer or for any
delay in



                                       21
<PAGE>   25

acting while waiting for those instructions. Any application by the Rights Agent
for written instructions from the Company may, at the option of the Rights
Agent, set forth in writing any action proposed to be taken or omitted by the
Rights Agent with respect to its duties or obligations under this Rights
Agreement and the date on and/or after which such action shall be taken or
omitted and the Rights Agent shall not be liable for any action taken or omitted
in accordance with a proposal included in any such application on or after the
date specified therein (which date shall not be less than three Business Days
after the date any such officer actually receives such application, unless any
such officer shall have consented in writing to an earlier date) unless, prior
to taking or omitting any such action, the Rights Agent has received written
instructions in response to such application specifying the action to be taken
or omitted.

               (i) The Rights Agent and any stockholder, director, officer or
employee of the Rights Agent may buy, sell or deal in any of the Rights or other
securities of the Company or become pecuniarily interested in any transaction in
which the Company may be interested, or contract with or lend money to the
Company or otherwise act as fully and freely as though it were not Rights Agent
under this Agreement. Nothing herein shall preclude the Rights Agent from acting
in any other capacity for the Company or for any other legal entity.

               (j) The Rights Agent may execute and exercise any of the rights
or powers hereby vested in it or perform any duty hereunder either itself or by
or through its attorneys or agents, and the Rights Agent shall not be answerable
or accountable for any act, default, neglect or misconduct of any such attorneys
or agents or for any loss to the Company resulting from any such act, default,
neglect or misconduct, provided reasonable care was exercised in the selection
and continued employment thereof.

        SECTION 21. CHANGE OF RIGHTS AGENT. The Rights Agent or any successor
Rights Agent may resign and be discharged from its duties under this Agreement
upon 30 days' notice in writing mailed to the Company and to each transfer agent
of the Common Shares or Preferred Shares by registered or certified mail, and to
the holders of the Right Certificates by first-class mail. The Company may
remove the Rights Agent or any successor Rights Agent upon 30 days' notice in
writing, mailed to the Rights Agent or successor Rights Agent, as the case may
be, and to each transfer agent of the Common Shares or Preferred Shares by
registered or certified mail, and to the holders of the Right Certificates by
first-class mail. If the Rights Agent shall resign or be removed or shall
otherwise become incapable of acting, the Company shall appoint a successor to
the Rights Agent. If the Company shall fail to make such appointment within a
period of 30 days after giving notice of such removal or after it has been
notified in writing of such resignation or incapacity by the resigning or
incapacitated Rights Agent or by the holder of a Right Certificate (who shall,
with such notice, submit such holder's Right Certificate for inspection by the
Company), then the registered holder of any Right Certificate may apply to any
court of competent jurisdiction for the appointment of a new Rights Agent. Any
successor Rights Agent, whether appointed by the Company or by such a court,
shall be (i) a corporation organized and doing business under the laws of the
United States or of the State of California (or of any other state of the United
States so long as such corporation is authorized to do business as a banking
institution in the State of California), in good standing, having an office in
the State of California, which is authorized under such laws to exercise
corporate trust or stock transfer powers and is subject to supervision or
examination by federal or state authority and which has at the time of its
appointment as Rights Agent a combined capital and surplus of at least $50



                                       22
<PAGE>   26

million dollars or (ii) a subsidiary of a corporation described in clause (i) of
this sentence. After appointment, the successor Rights Agent shall be vested
with the same powers, rights, duties and responsibilities as if it had been
originally named as Rights Agent without further act or deed; but the
predecessor Rights Agent shall deliver and transfer to the successor Rights
Agent any property at the time held by it hereunder, and execute and deliver any
further assurance, conveyance, act or deed necessary for the purpose. Not later
than the effective date of any such appointment the Company shall file notice
thereof in writing with the predecessor Rights Agent and each transfer agent of
the Common Shares or Preferred Shares, and mail a notice thereof in writing to
the registered holders of the Right Certificates. Failure to give any notice
provided for in this Section 21, however, or any defect therein, shall not
affect the legality or validity of the resignation or removal of the Rights
Agent or the appointment of the successor Rights Agent, as the case may be.

        SECTION 22. ISSUANCE OF NEW RIGHT CERTIFICATES. Notwithstanding any of
the provisions of this Agreement or of the Rights to the contrary, the Company
may, at its option, issue new Right Certificates evidencing Rights in such form
as may be approved by its Board of Directors to reflect any adjustment or change
in the Purchase Price and the number or kind or class of shares or other
securities or property purchasable under the Right Certificates made in
accordance with the provisions of this Agreement. In addition, following the
Distribution Date and prior to the redemption or expiration of the Rights, in
connection with the issuance or sale of Common Shares pursuant to the exercise
of stock options or under any employee plan or arrangement or upon the exercise,
conversion or exchange of other securities of the Company, in each case, which
options or securities are outstanding prior to the Distribution Date, the Board
of Directors shall issue Rights Certificates representing the appropriate number
of Rights in connection with such issuance or sale; provided, however, that (i)
no such Rights Certificate shall be issued and this sentence shall be null and
void ab initio if, and to the extent that, such issuance or this sentence would
create a significant risk of or result in material adverse tax consequences to
the Company or the Person to whom such Rights Certificate would be issued or
would create a significant risk of or result in such options' or employee plans'
or arrangements' failing to qualify for otherwise available special tax
treatment and (ii) no such Rights Certificate shall be issued if, and to the
extent that, appropriate adjustment shall otherwise have been made in lieu of
the issuance thereof.

        SECTION 23. REDEMPTION.

               (a) The Board of Directors of the Company may, by a resolution of
the Board of Directors, at its option, at any time prior to such time as any
Person becomes an Acquiring Person, redeem all but not less than all the then
outstanding Rights at a redemption price of $0.001 per Right, appropriately
adjusted to reflect any stock split, stock dividend or similar transaction
occurring after the date hereof (such redemption price being hereinafter
referred to as the "REDEMPTION PRICE"). After the period for redemption of the
Rights has expired, the Board of Directors may not extend the period for
redemption of the Rights or otherwise provide for their redemption. Subject to
the foregoing sentence, the redemption of the Rights by the Board of Directors
may be made effective at such time, on such basis and subject to such conditions
as the Board of Directors in its sole discretion may establish.



                                       23
<PAGE>   27

               (b) Immediately upon the action of the Board of Directors of the
Company ordering the redemption of the Rights pursuant to paragraph (a) of this
Section 23, and without any further action and without any notice, the right to
exercise the Rights will terminate and the only right thereafter of the holders
of Rights shall be to receive the Redemption Price. The Company shall promptly
give public notice of any such redemption; provided, however, that the failure
to give, or any defect in, any such notice shall not affect the validity of such
redemption. Within 10 days after such action of the Board of Directors ordering
the redemption of the Rights pursuant to paragraph (a), the Company shall mail a
notice of redemption to all the holders of the then outstanding Rights at their
last addresses as they appear upon the registry books of the Rights Agent or,
prior to the Distribution Date, on the registry books of the transfer agent for
the Common Shares. Any notice which is mailed in the manner herein provided
shall be deemed given, whether or not the holder receives the notice. If the
payment of the Redemption Price is not included in such notice, each such notice
shall state the method by which the payment of the Redemption Price will be
made. Neither the Company nor any of its Affiliates or Associates may redeem,
acquire or purchase for value any Rights at any time in any manner other than
that specifically set forth in this Section 23 or in Section 24 hereof, and
other than in connection with the purchase of Common Shares prior to the
Distribution Date.

        SECTION 24. EXCHANGE.

               (a) The Board of Directors of the Company may, at its option, at
any time after any Person becomes an Acquiring Person, authorize and direct the
exchange of all or part of the then outstanding and exercisable Rights (which
shall not include Rights that have become void pursuant to the provisions of
Section 11(a)(ii) hereof) for Common Shares at an exchange ratio (the "EXCHANGE
RATIO") of one Common Share per Right, appropriately adjusted to reflect any
stock split, stock dividend or similar transaction occurring after the date
hereof. Notwithstanding the foregoing, the Board of Directors shall not be
empowered to effect such exchange at any time after any Person (other than the
Company, any Subsidiary of the Company, any employee benefit plan of the Company
or any such Subsidiary or any entity holding Common Shares for or pursuant to
the terms of any such plan), together with all Affiliates and Associates of such
Person, becomes the Beneficial Owner of a majority of the Common Shares then
outstanding.

               (b) Immediately upon the action of the Board of Directors of the
Company ordering the exchange of any Rights pursuant Section 24(a) hereof and
without any further action and without any notice, the right to exercise such
Rights shall terminate and the only right thereafter of a holder of such Rights
shall be to receive that number of Common Shares equal to the number of such
Rights held by such holder multiplied by the Exchange Ratio. The Company shall
promptly give public notice of any such exchange; provided, however, that the
failure to give, or any defect in, such notice shall not affect the validity of
such exchange. The Company promptly shall mail a notice of any such exchange to
all of the holders of such Rights at their last addresses as they appear upon
the registry books of the Rights Agent. Any notice which is mailed in the manner
herein provided shall be deemed given, whether or not the holder receives the
notice. Each such notice of exchange will state the method by which the exchange
of the Common Shares for Rights will be effected and, in the event of any
partial exchange, the number of Rights which will be exchanged. Any partial
exchange shall be effected pro rata based on the



                                       24
<PAGE>   28

number of Rights (other than Rights which have become void pursuant to the
provisions of Section 11(a)(ii) hereof) held by each holder of Rights.

               (c) In any exchange pursuant to this Section 24, the Company, at
its option, may substitute Preferred Shares (or common stock equivalents, as
such term is defined in Section 11(a)(iii) hereof) for Common Shares
exchangeable for Rights, at the initial rate of one one-hundredth of a Preferred
Share (or common stock equivalents) for each Common Share, as appropriately
adjusted to reflect adjustments in the voting rights of the Preferred Shares
pursuant to the terms thereof, so that the fraction of a Preferred Share
delivered in lieu of each Common Share shall have the same voting rights as one
Common Share.

               (d) In the event that there shall not be sufficient Common
Shares, Preferred Shares or common stock equivalents authorized by the Company's
certificate of incorporation and not outstanding or subscribed for, or reserved
or otherwise committed for issuance for purposes other than upon exercise of
Rights, to permit any exchange of Rights as contemplated in accordance with this
Section 24, the Company shall take all such action as may be necessary to
authorize additional Common Shares, Preferred Shares or common stock equivalents
for issuance upon exchange of the Rights.

               (e) The Company shall not be required to issue fractions of
Common Shares or to distribute certificates which evidence fractional Common
Shares. In lieu of such fractional Common Shares, the Company shall pay to the
registered holders of the Right Certificates with regard to which such
fractional Common Shares would otherwise be issuable an amount in cash equal to
the same fraction of the current per share market value of a whole Common Share.
For the purposes of this paragraph (e), the current per share market value of a
whole Common Share shall be the closing price of a Common Share (as determined
pursuant to the second sentence of Section 11(d)(i) hereof) for the Trading Day
immediately prior to the date of exchange pursuant to this Section 24.

        SECTION 25. NOTICE OF CERTAIN EVENTS.

               (a) In case the Company shall propose (i) to pay any dividend
payable in stock of any class to the holders of its Preferred Shares or to make
any other distribution to the holders of its Preferred Shares (other than a
regular quarterly cash dividend), (ii) to offer to the holders of its Preferred
Shares rights or warrants to subscribe for or to purchase any additional
Preferred Shares or shares of stock of any class or any other securities, rights
or options, (iii) to effect any reclassification of its Preferred Shares (other
than a reclassification involving only the subdivision of outstanding Preferred
Shares), (iv) to effect any consolidation or merger into or with, or to effect
any sale or other transfer (or to permit one or more of its Subsidiaries to
effect any sale or other transfer), in one or more transactions, of 50% or more
of the assets or earning power of the Company and its Subsidiaries (taken as a
whole) to, any other Person, (v) to effect the liquidation, dissolution or
winding up of the Company, or (vi) to declare or pay any dividend on the Common
Shares payable in Common Shares or to effect a subdivision, combination or
consolidation of the Common Shares (by reclassification or otherwise than by
payment of dividends in Common Shares), then, in each such case, the Company
shall give to the Rights Agent and each holder of a Right Certificate, in
accordance with Section 26 hereof, a notice of such proposed action, which shall
specify the record date for the purposes of such stock



                                       25
<PAGE>   29

dividend, or distribution of rights or warrants, or the date on which such
reclassification, consolidation, merger, sale, transfer, liquidation,
dissolution, or winding up is to take place and the date of participation
therein by the holders of the Common Shares and/or Preferred Shares, if any such
date is to be fixed, and such notice shall be so given in the case of any action
covered by clause (i) or (ii) above at least 10 days prior to the record date
for determining holders of the Preferred Shares for purposes of such action, and
in the case of any such other action, at least 10 days prior to the date of the
taking of such proposed action or the date of participation therein by the
holders of the Common Shares and/or Preferred Shares, whichever shall be the
earlier.

               (b) In case any event set forth in Section 11(a)(ii) hereof shall
occur, then the Company shall as soon as practicable thereafter give to each
holder of a Right Certificate, in accordance with Section 26 hereof, a notice of
the occurrence of such event, which notice shall describe such event and the
consequences of such event to holders of Rights under Section 11(a)(ii) hereof.

        SECTION 26. NOTICES. Notices or demands authorized by this Agreement to
be given or made by the Rights Agent or by the holder of any Right Certificate
to or on the Company shall be sufficiently given or made if sent by first-class
mail, postage prepaid, addressed (until another address is filed in writing with
the Rights Agent) as follows:

               Large Scale Biology Corporation
               3333 Vaca Valley Parkway, Suite 1000
               Vacaville, CA 95688
               Attention:  Corporate Secretary

Subject to the provisions of Section 21 hereof, any notice or demand authorized
by this Agreement to be given or made by the Company or by the holder of any
Right Certificate to or on the Rights Agent shall be sufficiently given or made
if sent by first-class mail, postage prepaid, addressed (until another address
is filed in writing with the Company) as follows:

               Equiserve Trust Company, N.A.
               150 Royall Street
               Canton, MA 02021
               Attention:  Client Administration

Notices or demands authorized by this Agreement to be given or made by the
Company or the Rights Agent to the holder of any Right Certificate shall be
sufficiently given or made if sent by first-class mail, postage prepaid,
addressed to such holder at the address of such holder as shown on the registry
books of the Company.

        SECTION 27. SUPPLEMENTS AND AMENDMENTS. The Company may, by a resolution
of the Board of Directors of the Company, from time to time, and the Rights
Agent shall, if the Company directs, supplement or amend this Agreement without
the approval of any holders of Right Certificates in order to cure any
ambiguity, to correct or supplement any provision contained herein which may be
defective or inconsistent with any other provisions herein, or to make any other
provisions or changes with respect to the Rights which the Company may deem
necessary or desirable, including, without limitation, to modify or amend the
definition of



                                       26
<PAGE>   30

Acquiring Person set forth in Section 1(a) hereof, to change the Purchase Price
set forth in Section 7(b), or to extend or shorten the period for redemption of
the Rights; provided, however, that from and after such time as any Person
becomes an Acquiring Person, this Agreement shall not be amended in any manner
which would adversely affect the interests of the holders of Rights (other than
an Acquiring Person and its Affiliates and Associates), including, without
limitation, to extend the period for redemption of the Rights, or otherwise
provide for their redemption, or to provide for an earlier Final Expiration
Date. Any such supplement or amendment will be evidenced by a writing signed by
the Company and the Rights Agent. The Rights Agent shall not be obligated to
enter into any amendment or supplement to this Agreement which in the opinion of
the Rights Agent, may materially adversely affect the rights, duties,
liabilities to the Company or immunities to the Company of the Rights Agent.

        SECTION 28. SUCCESSORS. All the covenants and provisions of this
Agreement by or for the benefit of the Company or the Rights Agent shall bind
and inure to the benefit of their respective successors and assigns hereunder.

        SECTION 29. BENEFITS OF THIS AGREEMENT. Nothing in this Agreement shall
be construed to give to any person or corporation other than the Company, the
Rights Agent and the registered holders of the Right Certificates (and, prior to
the Distribution Date, the Common Shares) any legal or equitable right, remedy
or claim under this Agreement; but this Agreement shall be for the sole and
exclusive benefit of the Company, the Rights Agent and the registered holders of
the Right Certificates (and, prior to the Distribution Date, the Common Shares).

        SECTION 30. SEVERABILITY. If any term, provision, covenant or
restriction of this Agreement is held by a court of competent jurisdiction or
other authority to be invalid, void or unenforceable, then such term, provision,
covenant or restriction shall be enforced to the maximum extent permissible, and
the remainder of the terms, provisions, covenants and restrictions of this
Agreement shall remain in full force and effect and shall in no way be affected,
impaired or invalidated.

        SECTION 31. GOVERNING LAW. This Agreement and each Right Certificate
issued hereunder shall be deemed to be a contract made under the laws of the
State of Delaware and for all purposes shall be governed by and construed in
accordance with the laws of such State applicable to contracts to be made and
performed entirely within such State.

        SECTION 32. COUNTERPARTS. This Agreement may be executed in any number
of counterparts and each of such counterparts shall for all purposes be deemed
to be an original, and all such counterparts shall together constitute but one
and the same instrument.

        SECTION 33. DESCRIPTIVE HEADINGS. Descriptive headings of the several
Sections of this Agreement are inserted for convenience only and shall not
control or affect the meaning or construction of any of the provisions hereof.

        SECTION 34. ENTIRE AGREEMENT. This Agreement contains the entire
agreement between the parties with respect to the subject matter hereof.



                                       27
<PAGE>   31

        IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed and attested, all as of the day and year first above written.

COMPANY:

LARGE SCALE BIOLOGY CORPORATION

By:    /s/ Robert L. Erwin
       ---------------------------------------

Name:  Robert L. Erwin
       ---------------------------------------

Title: Chief Executive Officer
       ---------------------------------------



RIGHTS AGENT:

EQUISERVE TRUST COMPANY, N.A.

By:    /s/ Michael J. Connor
       ---------------------------------------

Name:  Michael J Connor
       ---------------------------------------

Title: Managing Director Client Administration
       ---------------------------------------



                      [SIGNATURE PAGE TO RIGHTS AGREEMENT]


                                       28
<PAGE>   32

                                    EXHIBIT A

                                      FORM

                                       OF

                           CERTIFICATE OF DESIGNATIONS

                                       OF

                  SERIES A JUNIOR PARTICIPATING PREFERRED STOCK

                                       OF

                         LARGE SCALE BIOLOGY CORPORATION


                         (Pursuant to Section 151 of the

                        Delaware General Corporation Law)

                -------------------------------------------------


        Large Scale Biology Corporation, a corporation organized and existing
under the General Corporation Law of the State of Delaware (hereinafter called
the "Corporation"), hereby certifies that the following resolution was adopted
by the Board of Directors of the Corporation as required by Section 151 of the
General Corporation Law at a meeting duly called and held on April 27, 2001:

        RESOLVED, that pursuant to the authority granted to and vested in the
Board of Directors of this Corporation (hereinafter called the "BOARD OF
DIRECTORS" or the "BOARD") in accordance with the provisions of the Certificate
of Incorporation of the Corporation, the Board of Directors hereby creates a
series of Preferred Stock, par value $0.001 per share (the "PREFERRED STOCK"),
of the Corporation and hereby states the designation and number of shares, and
fixes the relative rights, preferences, and limitations thereof as follows:

        Series A Junior Participating Preferred Stock:

        SECTION 1. DESIGNATION AND AMOUNT. The shares of such series shall be
designated as "SERIES A JUNIOR PARTICIPATING PREFERRED STOCK" (the "SERIES A
PREFERRED STOCK") and the number of shares constituting the Series A Preferred
Stock shall be Five Hundred Thousand (500,000). Such number of shares may be
increased or decreased by resolution of the Board of Directors; provided, that
no decrease shall reduce the number of shares of Series A Preferred Stock to a
number less than the number of shares then outstanding plus the number of shares
reserved for issuance upon the exercise of outstanding options, rights or
warrants or upon the conversion of any outstanding securities issued by the
Corporation convertible into Series A Preferred Stock.



                                       1
<PAGE>   33

        SECTION 2. DIVIDENDS AND DISTRIBUTIONS.

               (a) Subject to the rights of the holders of any shares of any
series of Preferred Stock (or any other stock) ranking prior and superior to the
Series A Preferred Stock with respect to dividends, the holders of shares of
Series A Preferred Stock shall be entitled to receive, when, as and if declared
by the Board of Directors out of funds legally available for the purpose,
quarterly dividends payable in cash on the first day of March, June, September
and December in each year (each such date being referred to herein as a
"Quarterly Dividend Payment Date"), commencing on the first Quarterly Dividend
Payment Date after the first issuance of a share or fraction of a share of
Series A Preferred Stock, in an amount (if any) per share (rounded to the
nearest cent), subject to the provision for adjustment hereinafter set forth,
equal to 100 times the aggregate per share amount of all cash dividends, and 100
times the aggregate per share amount (payable in kind) of all non-cash dividends
or other distributions, other than a dividend payable in shares of Common Stock,
par value $0.001 per share (the "COMMON STOCK"), of the Company or a subdivision
of the outstanding shares of Common Stock (by reclassification or otherwise),
declared on the Common Stock since the immediately preceding Quarterly Dividend
Payment Date or, with respect to the first Quarterly Dividend Payment Date,
since the first issuance of any share or fraction of a share of Series A
Preferred Stock. In the event the Corporation shall at any time declare or pay
any dividend on the Common Stock payable in shares of Common Stock, or effect a
subdivision or combination or consolidation of the outstanding shares of Common
Stock (by reclassification or otherwise than by payment of a dividend in shares
of Common Stock) into a greater or lesser number of shares of Common Stock, then
in each such case the amount to which holders of shares of Series A Preferred
Stock were entitled immediately prior to such event under the preceding sentence
shall be adjusted by multiplying such amount by a fraction, the numerator of
which is the number of shares of Common Stock outstanding immediately after such
event and the denominator of which is the number of shares of Common Stock that
were outstanding immediately prior to such event.

               (b) The Corporation shall declare a dividend or distribution on
the Series A Preferred Stock as provided in paragraph (a) of this Section
immediately after it declares a dividend or distribution on the Common Stock
(other than a dividend payable in shares of Common Stock).

               (c) Dividends due pursuant to paragraph (a) of this Section shall
begin to accrue and be cumulative on outstanding shares of Series A Preferred
Stock from the Quarterly Dividend Payment Date next preceding the date of issue
of such shares, unless the date of issue of such shares is prior to the record
date for the first Quarterly Dividend Payment Date, in which case dividends on
such shares shall begin to accrue from the date of issue of such shares, or
unless the date of issue is a Quarterly Dividend Payment Date or is a date after
the record date for the determination of holders of shares of Series A Preferred
Stock entitled to receive a quarterly dividend and before such Quarterly
Dividend Payment Date, in either of which events such dividends shall begin to
accrue and be cumulative from such Quarterly Dividend Payment Date. Accrued but
unpaid dividends shall not bear interest. Dividends paid on the shares of Series
A Preferred Stock in an amount less than the total amount of such dividends at
the time accrued and payable on such shares shall be allocated pro rata on a
share-by-share basis among all such shares at the time outstanding. The Board of
Directors may fix a record date for the determination of holders of shares of
Series A Preferred Stock entitled to receive payment of a



                                       2
<PAGE>   34

dividend or distribution declared thereon, which record date shall be not more
than 60 days prior to the date fixed for the payment thereof.

        SECTION 3. VOTING RIGHTS. The holders of shares of Series A Preferred
Stock shall have the following voting rights:

               (a) Subject to the provision for adjustment hereinafter set
forth, each share of Series A Preferred Stock shall entitle the holder thereof
to 100 votes on all matters submitted to a vote of the stockholders of the
Corporation. In the event the Corporation shall at any time declare or pay any
dividend on the Common Stock payable in shares of Common Stock, or effect a
subdivision or combination or consolidation of the outstanding shares of Common
Stock (by reclassification or otherwise than by payment of a dividend in shares
of Common Stock) into a greater or lesser number of shares of Common Stock, then
in each such case the number of votes per share to which holders of shares of
Series A Preferred Stock were entitled immediately prior to such event shall be
adjusted by multiplying such number by a fraction, the numerator of which is the
number of shares of Common Stock outstanding immediately after such event and
the denominator of which is the number of shares of Common Stock that were
outstanding immediately prior to such event.

               (b) Except as otherwise provided herein, in any other Certificate
of Designations creating a series of Preferred Stock or any similar stock, or by
law, the holders of shares of Series A Preferred Stock and the holders of shares
of Common Stock and any other capital stock of the Corporation having general
voting rights shall vote together as one class on all matters submitted to a
vote of stockholders of the Corporation.

               (c) Except as set forth herein, or as otherwise provided by law,
holders of Series A Preferred Stock shall have no special voting rights and
their consent shall not be required (except to the extent they are entitled to
vote with holders of Common Stock as set forth herein) for taking any corporate
action.

        SECTION 4. CERTAIN RESTRICTIONS.

               (a) Whenever quarterly dividends or other dividends or
distributions payable on the Series A Preferred Stock as provided in Section 2
are in arrears, thereafter and until all accrued and unpaid dividends and
distributions, whether or not declared, on shares of Series A Preferred Stock
outstanding shall have been paid in full, the Corporation shall not:

                      (i) declare or pay dividends, or make any other
distributions, on any shares of stock ranking junior (either as to dividends or
upon liquidation, dissolution or winding up) to the Series A Preferred Stock;

                      (ii) declare or pay dividends, or make any other
distributions, on any shares of stock ranking on a parity (either as to
dividends or upon liquidation, dissolution or winding up) with the Series A
Preferred Stock, except dividends paid ratably on the Series A Preferred Stock
and all such parity stock on which dividends are payable or in arrears in
proportion to the total amounts to which the holders of all such shares are then
entitled; or



                                       3
<PAGE>   35

                      (iii) redeem or purchase or otherwise acquire for
consideration shares of any stock ranking junior (either as to dividends or upon
liquidation, dissolution or winding up) to the Series A Preferred Stock,
provided that the Corporation may at any time redeem, purchase or otherwise
acquire shares of any such junior stock in exchange for shares of any stock of
the Corporation ranking junior (as to dividends and upon dissolution,
liquidation or winding up) to the Series A Preferred Stock.

               (b) The Corporation shall not permit any subsidiary of the
Corporation to purchase or otherwise acquire for consideration any shares of
stock of the Corporation unless the Corporation could, under paragraph (a) of
this Section 4, purchase or otherwise acquire such shares at such time and in
such manner.

        SECTION 5. REACQUIRED SHARES. Any shares of Series A Preferred Stock
purchased or otherwise acquired by the Corporation in any manner whatsoever
shall be retired and cancelled promptly after the acquisition thereof. All such
shares shall upon their cancellation become authorized but unissued shares of
Preferred Stock and may be reissued as part of a new series of Preferred Stock
subject to the conditions and restrictions on issuance set forth herein, in the
Certificate of Incorporation, or in any other Certificate of Designations
creating a series of Preferred Stock or any similar stock or as otherwise
required by law.

        SECTION 6. LIQUIDATION, DISSOLUTION OR WINDING UP.

               (a) Upon any liquidation, dissolution or winding up of the
Corporation, the holders of shares of Series A Preferred Stock shall be entitled
to receive, prior and in preference to any distribution of any assets of the
Corporation to the holders of Common Stock, the amount of $1.00 per share for
each share of Series A Preferred Stock then held by them. Thereafter, the
holders of shares of Series A Preferred Stock shall be entitled to receive an
aggregate amount per share, subject to the provision for adjustment hereinafter
set forth, equal to 100 times the aggregate amount to be distributed per share
to holders of shares of Common Stock plus an amount equal to any accrued and
unpaid dividends. In the event the Corporation shall at any time declare or pay
any dividend on the Common Stock payable in shares of Common Stock, or effect a
subdivision or combination or consolidation of the outstanding shares of Common
Stock (by reclassification or otherwise than by payment of a dividend in shares
of Common Stock) into a greater or lesser number of shares of Common Stock, then
in each such case the aggregate amount to which holders of shares of Series A
Preferred Stock were entitled immediately prior to such event under the
preceding sentence shall be adjusted by multiplying such amount by a fraction
the numerator of which is the number of shares of Common Stock outstanding
immediately after such event and the denominator of which is the number of
shares of Common Stock that were outstanding immediately prior to such event.

               (b) If the assets of the Corporation legally available for
distribution to the holders of shares of Series A Preferred Stock upon
liquidation, dissolution or winding up of the Corporation are insufficient to
pay the full preferential amount set forth in the first sentence of paragraph
(a) above, then the entire assets of the Corporation legally available for
distribution to the holders of Series A Preferred Stock shall be distributed
among such holders in proportion to the shares of Series A Preferred Stock then
held by them.



                                       4
<PAGE>   36

               (c) The foregoing rights upon liquidation, dissolution or winding
up provided to the holders of Series A Preferred Stock shall be subject to the
rights of the holders of any other series of Preferred Stock (or any other
stock) ranking prior and superior to the Series A Preferred Stock upon
liquidation, dissolution or winding up.

        SECTION 7. CONSOLIDATION, MERGER, ETC. In case the Corporation shall
enter into any consolidation, merger, combination or other transaction in which
the shares of Common Stock are exchanged for or changed into other stock or
securities, cash and/or other property, then in any such case each share of
Series A Preferred Stock shall at the same time be similarly exchanged or
changed into an amount per share, subject to the provision for adjustment
hereinafter set forth, equal to 100 times the aggregate amount of stock,
securities, cash and/or any other property (payable in kind), as the case may
be, into which or for which each share of Common Stock is changed or exchanged.
In the event the Corporation shall at any time declare or pay any dividend on
the Common Stock payable in shares of Common Stock, or effect a subdivision or
combination or consolidation of the outstanding shares of Common Stock (by
reclassification or otherwise than by payment of a dividend in shares of Common
Stock) into a greater or lesser number of shares of Common Stock, then in each
such case the amount set forth in the preceding sentence with respect to the
exchange or change of shares of Series A Preferred Stock shall be adjusted by
multiplying such amount by a fraction, the numerator of which is the number of
shares of Common Stock outstanding immediately after such event and the
denominator of which is the number of shares of Common Stock that were
outstanding immediately prior to such event.

        SECTION 8. NO REDEMPTION. The shares of Series A Preferred Stock shall
not be redeemable.



                                       5
<PAGE>   37

        IN WITNESS WHEREOF, this Certificate of Designations is executed on
behalf of the Corporation this ____ day of _______, 2001.



LARGE SCALE BIOLOGY CORPORATION


By:
    ------------------------------------
    Robert L. Erwin
    Chief Executive Officer



                 [SIGNATURE PAGE TO CERTIFICATE OF DESIGNATIONS]


                                       6
<PAGE>   38

                                    EXHIBIT B

                            FORM OF RIGHT CERTIFICATE


Certificate No. R-__                                                _____ Rights

               NOT EXERCISABLE AFTER APRIL 27, 2011 OR EARLIER IF REDEMPTION OR
               EXCHANGE OCCURS. THE RIGHTS ARE SUBJECT TO REDEMPTION AT $0.001
               PER RIGHT AND TO EXCHANGE ON THE TERMS SET FORTH IN THE RIGHTS
               AGREEMENT.

                                RIGHT CERTIFICATE

                         LARGE SCALE BIOLOGY CORPORATION

        This certifies that ____________________ or registered assigns, is the
registered owner of the number of Rights set forth above, each of which entitles
the owner thereof, subject to the terms, provisions and conditions of the Rights
Agreement, dated as of April 27, 2001 (the "RIGHTS AGREEMENT"), between Large
Scale Biology Corporation, a Delaware corporation (the "COMPANY"), and Equiserve
Trust Company, N.A. (the "RIGHTS AGENT"), to purchase from the Company at any
time after the Distribution Date (as such term is defined in the Rights
Agreement) and prior to 5:00 p.m., Pacific Time, on April 27, 2011 at the
principal office of the Rights Agent, or at the office of its successor as
Rights Agent, one one-hundredth of a fully paid non-assessable share of Series A
Junior Participating Preferred Stock, par value $0.001 per share (the "PREFERRED
SHARES"), of the Company, at a purchase price of $45.00 per one one-hundredth
(1/100) of a Preferred Share (the "PURCHASE PRICE"), upon presentation and
surrender of this Right Certificate with the Certification and the Form of
Election to Purchase duly executed. The number of Rights evidenced by this Right
Certificate (and the number of one one-hundredths of a Preferred Share which may
be purchased upon exercise hereof) set forth above, and the Purchase Price set
forth above, are the number and Purchase Price as of ____________ 2001, based on
the Preferred Shares as constituted at such date. As provided in the Rights
Agreement, the Purchase Price and the number of one one-hundredths of a
Preferred Share which may be purchased upon the exercise of the Rights evidenced
by this Right Certificate are subject to modification and adjustment upon the
happening of certain events.

        This Right Certificate is subject to all of the terms, provisions and
conditions of the Rights Agreement, which terms, provisions and conditions are
hereby incorporated herein by reference and made a part hereof and to which
Rights Agreement reference is hereby made for a full description of the rights,
limitations of rights, obligations, duties and immunities hereunder of the
Rights Agent, the Company and the holders of the Right Certificates. Copies of
the Rights Agreement are on file at the principal executive offices of the
Company and the above-mentioned offices of the Rights Agent.

<PAGE>   39

        This Right Certificate, with or without other Right Certificates, upon
surrender at the principal office of the Rights Agent, may be exchanged for
another Right Certificate or Right Certificates of like tenor and date
evidencing Rights entitling the holder to purchase a like aggregate number of
Preferred Shares as the Rights evidenced by the Right Certificate or Right
Certificates surrendered shall have entitled such holder to purchase. If this
Right Certificate shall be exercised in part, the holder shall be entitled to
receive upon surrender hereof another Right Certificate or Right Certificates
for the number of whole Rights not exercised.

        Subject to the provisions of the Rights Agreement, the Rights evidenced
by this Certificate (i) may be redeemed by the Company at a redemption price of
$0.001 per Right or (ii) may be exchanged in whole or in part for Preferred
Shares or shares of the Company's Common Stock, par value $0.001 per share.

        No fractional Preferred Shares will be issued upon the exercise of any
Right or Rights evidenced hereby (other than fractions which are integral
multiples of one one-hundredth of a Preferred Share, which may, at the election
of the Company, be evidenced by depository receipts), but in lieu thereof a cash
payment will be made, as provided in the Rights Agreement.

        No holder of this Right Certificate shall be entitled to vote or receive
dividends or be deemed for any purpose the holder of the Preferred Shares or of
any other securities of the Company which may at any time be issuable on the
exercise hereof, nor shall anything contained in the Rights Agreement or herein
be construed to confer upon the holder hereof, as such, any of the rights of a
stockholder of the Company or any right to vote for the election of directors or
upon any matter submitted to stockholders at any meeting thereof, or to give or
withhold consent to any corporate action, or to receive notice of meetings or
other actions affecting stockholders (except as provided in the Rights
Agreement), or to receive dividends or subscription rights, or otherwise, until
the Right or Rights evidenced by this Right Certificate shall have been
exercised as provided in the Rights Agreement.

        This Right Certificate shall not be valid or obligatory for any purpose
until it shall have been countersigned by the Rights Agent.



                                       2
<PAGE>   40

        WITNESS the facsimile signature of the proper officers of the Company
and its corporate seal.

Dated as of                , 2001
            ---------------

ATTEST:                                      LARGE SCALE BIOLOGY CORPORATION


By                                           By
   --------------------------------             --------------------------------

Name:                                        Name:
      -----------------------------                -----------------------------

Its:                                         Its:
     ------------------------------               ------------------------------

Countersigned:


EQUISERVE TRUST COMPANY, N.A.

By
   --------------------------------

Name:
      -----------------------------

Its:
     ------------------------------



                  [SIGNATURE PAGE TO FORM OF RIGHT CERTIFICATE]

<PAGE>   41

                    FORM OF REVERSE SIDE OF RIGHT CERTIFICATE


                               FORM OF ASSIGNMENT

                (To be executed by the registered holder if such
                holder desires to transfer the Right Certificate)


        FOR VALUE RECEIVED ___________________________________ hereby sells,
assigns and transfers unto ___________________________________________________
(Please print name and address of transferee) this Right Certificate, together
with all right, title and interest therein, and does hereby irrevocably
constitute and appoint __________________________________________________,
Attorney, to transfer the within Right Certificate on the books of the
within-named Company, with full power of substitution.

Dated:
        ------------------------


                                             -----------------------------------
                                             Signature



Signature(s) Guaranteed:


        SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION
(BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH
MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM), PURSUANT TO
S.E.C. RULE 17Ad-15


                     ---------------------------------------


        The undersigned hereby certifies that the Rights evidenced by this Right
Certificate are not beneficially owned by an Acquiring Person or an Affiliate or
Associate thereof (as defined in the Rights Agreement).



                                             -----------------------------------
                                             Signature



                  [SIGNATURE PAGE TO FORM OF RIGHT CERTIFICATE]

<PAGE>   42

              Form of Reverse Side of Right Certificate--continued

                          FORM OF ELECTION TO PURCHASE

      (To be executed if holder desires to exercise the Right Certificate)



To _______________________:


        The undersigned hereby irrevocably elects to exercise _____________
Rights represented by this Right Certificate to purchase the Preferred Shares
issuable upon the exercise of such Rights and requests that certificates for
such Preferred Shares be issued in the name of:

Please insert social security or other identifying number:


----------------------------------------------------------
(Please print name and address)

----------------------------------------------------------

----------------------------------------------------------

If such If such number of Rights shall not be all the Rights evidenced by this
Right Certificate, a new Right Certificate for the balance remaining of such
Rights shall be registered in the name of and delivered to:

----------------------------------------------------------
(Please print name and address)

----------------------------------------------------------

----------------------------------------------------------

Dated:
        ------------------------


                                             -----------------------------------
                                             Signature


Signature(s) Guaranteed:

        SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION
(BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH
MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM), PURSUANT TO
S.E.C. RULE 17Ad-15.



                                       2
<PAGE>   43

              Form of Reverse Side of Right Certificate--continued


                     ---------------------------------------


        The undersigned hereby certifies that the Rights evidenced by this Right
Certificate are not beneficially owned by an Acquiring Person or an Affiliate or
Associate thereof (as such terms are defined in the Rights Agreement).

Dated:
        ------------------------


                                             -----------------------------------
                                             Signature



                     ---------------------------------------


                                     NOTICE

        The signature in the foregoing Forms of Assignment and Election must
conform to the name as written upon the face of this Right Certificate in every
particular, without alteration or any change whatsoever.

        In the event the certification set forth above in the Form of Assignment
or the Form of Election to Purchase, as the case may be, is not completed, the
Company and the Rights Agent will deem the beneficial owner of the Rights
evidenced by this Right Certificate to be an Acquiring Person or an Affiliate or
Associate thereof (as defined in the Rights Agreement) and such Assignment or
Election to Purchase will not be honored.



                                       3
<PAGE>   44

                                    EXHIBIT C

                          SUMMARY OF RIGHTS TO PURCHASE
                                PREFERRED SHARES

        On April 27, 2001, the Board of Directors of Large Scale Biology
Corporation (the "COMPANY") declared a dividend of one (1) preferred share
purchase right (a "RIGHT") for each outstanding share of common stock, par value
$0.001 per share (the "COMMON SHARES"), of the Company. The dividend is payable
to stockholders of record on May 4, 2001 (the "RECORD DATE"). In addition, one
Right will be issued with each share of Company common stock that becomes
outstanding (i) between the Record Date and the earliest of the Distribution
Date (as defined below), the date the Rights are redeemed and the date the
Rights expire or (ii) following the Distribution Date and prior to the date the
Rights are redeemed and the date the Rights expire, pursuant to the exercise of
employee stock options or upon the exercise, conversion or exchange of other
securities of the Company, outstanding prior to the Distribution Date. Each
Right entitles the registered holder to purchase from the Company one
one-hundredth of a share of The Company Series A Junior Participating Preferred
Stock (the "PREFERRED SHARES") at a price of $45.00 per one one-hundredth of a
Preferred Share (the "PURCHASE PRICE"), subject to adjustment. A complete
description of the terms of the Rights are set forth in a Rights Agreement
between the Company and Equiserve Trust Company, N.A., as Rights Agent.

        Until the earlier to occur of (i) 10 days following a public
announcement or disclosure that a person or group of affiliated or associated
persons (an "ACQUIRING PERSON"), has acquired beneficial ownership of 15% or
more of the Company's outstanding common stock or (ii) 10 business days (or a
later date determined by the Company's Board of Directors before a person or
group becomes an Acquiring Person), following the announcement of an intention
to make a tender offer or exchange offer the consummation of which would result
in a person or group becoming an Acquiring Person (the earlier of such dates
being called the "DISTRIBUTION DATE"), the Rights will be represented by common
stock certificates with a copy of this Summary of Rights attached. No person or
group will become an Acquiring Person if the Company's Board of Directors
determines that such person crossed the ownership threshold inadvertently, and
such person or group promptly sells shares of Company common stock until they
own less than 15% of the outstanding common stock.

        The Rights Agreement provides that, until the Distribution Date, the
Rights will be transferred only with Company common stock. Until the
Distribution Date (or earlier redemption or expiration of the Rights), new
common stock certificates issued after the Record Date will contain a notation
incorporating the Rights Agreement by reference. Until the Distribution Date (or
earlier redemption or expiration of the Rights), the transfer of any common
stock certificates, even without such notation or a copy of this Summary of
Rights being attached, will also constitute the transfer of the Rights
associated with the Company common stock represented by such certificate. After
the Distribution Date, separate certificates representing the Rights will be
mailed to record holders of Company common stock on the Distribution Date and
such separate certificates alone will evidence the Rights. If shares of Company
common stock are issued or sold after the Distribution Date (but prior to the
redemption or expiration of the Rights) in connection with the exercise of stock
options or upon



                                       1
<PAGE>   45

the exercise, conversion or exchange of other securities of the Company
outstanding prior to the Distribution Date, the Company shall issue the
appropriate number of Rights in connection with such issuance or sale.

        The Rights are not exercisable until the Distribution Date. The Rights
will expire on April 27, 2011, unless the expiration date is extended or unless
the Rights are earlier redeemed or exchanged by the Company, as described below.
Until a Right is exercised, the holder of a Right, as such, will have no rights
as a stockholder of the Company.

        The purchase price payable, and the number of Preferred Shares or other
securities or property issuable, upon exercise of the Rights are subject to
adjustment from time to time to prevent dilution. The number of outstanding
Rights and the number of one one-hundredths of a Preferred Share issuable upon
exercise of each Right are also subject to adjustment upon certain events
occurring before the Distribution Date.

        The Preferred Shares have been structured so that each Preferred Share
has dividend, liquidation and voting rights equal to those of 100 shares of
Company common stock. Because of this, the value of the one one-hundredth
interest in a Preferred Share purchasable upon exercise of each Right should
approximate the value of one Common Share. The Preferred Shares are not
redeemable.

        In the event that any person owns more than 15% of the Company's
outstanding common stock and thereby becomes an Acquiring Person, unless the
event causing the person to become an Acquiring Person is a merger, acquisition
or other business combination described in the next paragraph, each holder of a
Right, other than Rights beneficially owned by the Acquiring Person (which will
thereafter be void), will thereafter have the right to receive upon exercise and
payment of the exercise price that number of shares of common stock having a
market value of two times the exercise price of the Right. If the Company does
not have enough authorized but unissued shares of common stock to satisfy this
obligation to issue common shares, the Company will deliver upon payment of the
exercise price of a Right an amount of cash or other securities equivalent in
value to the common stock issuable upon exercise of a Right.

        In the event that any person or group becomes an Acquiring Person and
the Company merges into or engages in certain other business combinations with
an Acquiring Person, or 50% or more of its consolidated assets or earning power
are sold to an Acquiring Person, each holder of a Right, other than Rights owned
by an Acquiring Person, will thereafter have the right to receive, upon exercise
and payment of the exercise price, that number of shares of common stock of the
acquiring company which at the time of such transaction will have a market value
of two times the exercise price of the Right.

        At any time after a person or group becomes an Acquiring Person and
prior to such person acquiring a majority of the outstanding Company common
stock, the Company Board of Directors may exchange all or some of the Rights
(other than Rights owned by the Acquiring Person), at an exchange ratio of one
common share, or one one-hundredth of a Preferred Share (or other equivalent
securities), per Right.



                                       2
<PAGE>   46

        At any time before a person or group becomes an Acquiring Person, the
Company Board of Directors may redeem all (but not some) of the Rights at a
price of $0.001 per Right and on such terms and conditions as the Board of
Directors may establish. After the period for redemption of the Rights has
expired, the Board may not amend the Rights Agreement to extend the period for
redemption of the Rights. Immediately upon any redemption of the Rights, the
right to exercise the Rights will terminate and the only right of the holders of
Rights will be to receive the redemption price.

        The terms of the Rights may be amended by a resolution of the Board of
Directors without the consent of the holders of the Rights, except that after a
person or group becomes an Acquiring Person, no such amendment may adversely
affect the interests of the holders of the Rights (other than an Acquiring
Person).

        A copy of the Rights Agreement has been filed with the Securities and
Exchange Commission as an Exhibit to a Registration Statement on Form 8-A dated
________, 2001. A copy of the Rights Agreement is available free of charge from
the Company. This summary description of the Rights does not purport to be
complete and is qualified in its entirety by reference to the Rights Agreement,
which is deemed to be incorporated into this summary.



                                       3