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                                                                     EXHIBIT 4.1



                          NINTH SUPPLEMENTAL INDENTURE


        NINTH SUPPLEMENTAL INDENTURE, dated as of September 29, 1997 (this
"Ninth Supplemental Indenture"), among Spieker Properties, Inc., a corporation
organized under the laws of Maryland (the "General Partner"), Spieker
Properties, L.P., a limited partnership organized under the laws of California
(the "Issuer"), First Trust of California, National Association, as Trustee (the
"Trustee") and State Street Bank and Trust Company ("State Street.").

                              W I T N E S S E T H:

        WHEREAS, the Issuer, the General Partner and State Street executed and
delivered an Indenture, dated as of December 6, 1995 (as supplemented hereby,
the "Indenture"), to provide for the issuance by the Issuer from time to time of
debt securities evidencing its unsecured indebtedness;

        WHEREAS, pursuant to Section 609(b) of the Indenture, the Issuer and the
General Partner desire to appoint the Trustee as trustee with respect to the
series of securities established by this Supplemental Indenture and future
series of securities under the Indenture;

        WHEREAS, the Issuer and the General Partner desire that State Street
remain trustee of all former series of securities issued under the Indenture;

        WHEREAS, pursuant to Board Resolution, the Issuer has authorized the
issuance of $150,000,000 of its 7.50% Debentures Due October 1, 2027 (the
"Notes");

        WHEREAS, the Issuer desires to establish the terms of the Notes in
accordance with Section 301 of the Indenture and to establish the form of the
Notes in accordance with Section 201 of the Indenture.


                                    ARTICLE 1

                        APPOINTMENT OF SUCCESSOR TRUSTEE

        SECTION 101. APPOINTMENT OF SUCCESSOR TRUSTEE. Pursuant to Section
609(b) of the Indenture, the Issuer and the General Partner hereby appoint the
Trustee as trustee, with all rights, powers, trusts and duties provided for in
the Indenture, for the series of securities established by this Supplemental
Indenture and, until the Issuer and the General Partner appoint another trustee
pursuant to the applicable provisions of the Indenture, for all future series of
securities issued under the Indenture, and the Trustee hereby accepts such
appointment.




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        SECTION 102. OUTSTANDING SECURITIES. State Street shall remain trustee
for securities outstanding on the date hereof and not issued pursuant to this
Supplemental Indenture and shall retain all rights, powers, trusts and duties
with respect to such securities.

        SECTION 103. NO CHANGES IN DUTIES OF TRUSTEE. Except as otherwise
provided in herein, there shall be no change, modification or amendment of the
powers, rights and duties of any trustee under the Indenture.

        SECTION 104. DESIGNATION OF ADDITIONAL AGENCY FOR PAYMENT. Pursuant to
Section 1002 of the Indenture, the Issuer hereby appoints the corporate trust
office of the Trustee, which, as of the date hereof, is located in care of First
Trust National Association, 180 E. Fifth Street, St. Paul, Minnesota 55101 (the
"Corporate Trust Office"), as its agent to receive presentations and surrenders,
and the corporate trust office of the Trustee at One California Street, Suite
400, San Francisco, California 94111, as its agent to receive notices and
demands, of securities issued under the Indenture from the date hereof and
hereafter.

                                    ARTICLE 2

                                      TERMS

        SECTION 201. TERMS OF NOTES. The following terms relating to the Notes
are hereby established:

               (1) The Notes shall constitute a series of Securities having the
        title "7.50% Debentures Due October 1, 2027."

               (2) The aggregate principal amount of the Notes that may be
        authenticated and delivered under the Indenture (except for Notes
        authenticated and delivered upon registration of transfer of, or in
        exchange for, or in lieu of, other Notes pursuant to Sections 304, 305,
        306, 906, 1107 or 1305 of the Indenture) shall be up to $150,000,000.

               (3) The entire outstanding principal of the Notes shall be
        payable on October 1, 2027 (the "Stated Maturity Date").

               (4) The rate at which the Notes shall bear interest shall be
        7.50%; the date from which interest shall accrue shall be September 29,
        1997; the Interest Payment Dates for the Notes on which interest will be
        payable shall be October 1 and April 1 in each year, beginning April 1,
        1998; the Regular Record Dates for the interest payable on the Notes on
        any Interest Payment Date shall be the 15th calendar day preceding the
        applicable Interest Payment Date; and the basis upon which interest
        shall be calculated shall be that of a 360-day year consisting of twelve
        30-day months.




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               (5) The Place of Payment where the principal of and interest on
        the Notes shall be payable and Notes may be surrendered for the
        registration of transfer or exchange shall be the Corporate Trust Office
        of the Trustee in St. Paul, Minnesota. The place where notices or
        demands to or upon the Issuer in respect of the Notes and the Indenture
        may be served shall be the corporate trust office of the Trustee at One
        California Street, Suite 400, San Francisco, California 94111.

               (6) (A) The Notes may be redeemed at any time at the option of
        the Issuer, in whole or from time to time in part, at a redemption price
        equal to the sum of (i) the principal amount of the Notes (or portion
        thereof) being redeemed plus accrued interest thereon to the redemption
        date and (ii) the Make-Whole Amount (as defined below), if any, with
        respect to such Notes (or portion thereof) (the "Redemption Price").

                      If notice has been given as provided in the Indenture and
        funds for the redemption of any Notes (or any portion thereof) called
        for redemption shall have been made available on the redemption date
        referred to in such notice, such Notes (or any portion thereof) will
        cease to bear interest on the date fixed for such redemption specified
        in such notice and the only right of the Holders of the Notes will be to
        receive payment of the Redemption Price, with respect to such Notes or
        portion thereof so redeemed.

                      Notice of any optional redemption of any Notes (or any
        portion thereof) will be given to Holders at their addresses, as shown
        in the security register for the Notes, not more than 60 nor less than
        30 days prior to the date fixed for redemption. The notice of redemption
        will specify, among other items, the Redemption Price and the principal
        amount of the Notes held by such Holder to be redeemed. On the third
        Business Day preceding the date notice of redemption is given, the
        Company will notify the Trustee of the Redemption Price and the Trustee
        may rely and shall be fully protected in acting upon the determination
        of the Company as to such Redemption Price.

                      The Issuer will notify the Trustee in writing at least 45
        days prior to giving notice of redemption (or such shorter period as is
        satisfactory to the Trustee in its sole discretion) of the aggregate
        principal amount of Notes to be redeemed and their redemption date. If
        less than all the Notes are to be redeemed at the option of the Issuer,
        the Trustee shall select by lot, the Notes to be redeemed in whole or in
        part.

                      In the event of redemption of the Notes in part only, a
        new Note for the amount of the unredeemed portion thereof shall be
        issued in the name of the Holder thereto, upon cancellation thereof.

                      (B) As used herein:

                      "Make-Whole Amount" means, in connection with any optional
        redemption or accelerated payment of any Notes, the excess, if any, of
        (i) the aggregate present value as of the date of such redemption or
        accelerated payment of each dollar of




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        principal being redeemed or paid and the amount of interest (exclusive
        of interest accrued to the date of redemption or accelerated payment)
        that would have been payable in respect of each such dollar if such
        redemption or accelerated payment had not been made, determined by
        discounting, on a semi-annual basis, such principal and interest at the
        Reinvestment Rate (determined on the third Business Day preceding the
        date such notice of redemption is given or declaration of acceleration
        is made) from the respective dates on which such principal and interest
        would have been payable if such redemption or accelerated payment had
        not been made, over (ii) the aggregate principal amount of the Notes
        being redeemed or paid.

                      "Reinvestment Rate" means 0.25% plus the arithmetic mean
        of the yields under the respective heading "Week Ending" published in
        the most recent Statistical Release under the caption "Treasury Constant
        Maturities" for the maturity (rounded to the nearest month)
        corresponding to the remaining life to maturity, as of the payment date
        of the principal being redeemed or paid. If no maturity exactly
        corresponds to such maturity, yields for the two published maturities
        most closely corresponding to such maturity shall be calculated pursuant
        to the immediately preceding sentence and the Reinvestment Rate shall be
        interpolated or extrapolated from such yields on a straight-line basis,
        rounding in each of such relevant periods to the nearest month. For the
        purpose of calculating the Reinvestment Rate, the most recent
        Statistical Release published prior to the date of determination of the
        Make-Whole Amount shall be used.

                      "Statistical Release" means the statistical release
        designated "H.15(519)" or any successor publication which is published
        weekly by the Federal Reserve System and which establishes yields on
        actively traded United States government securities adjusted to constant
        maturities, or, if such statistical release is not published at the time
        of any determination under the Indenture, then such other reasonably
        comparable index which shall be designated by the Issuer.

               (7) The Notes shall not be redeemable at the option of any Holder
        thereof, upon the occurrence of any particular circumstances or
        otherwise. The Notes will not have the benefit of any sinking fund.

               (8) The Notes shall be issuable in denominations of $1,000 and
        any integral multiple thereof.

               (9) The Trustee shall also be the Security Registrar and Paying
        Agent for the Notes.

               (10) The entire outstanding principal amount plus the Make-Whole
        Amount of the Notes shall be payable upon declaration of acceleration of
        the maturity thereof pursuant to Section 502 of the Indenture.




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               (11) Payments of the principal of and interest on the Notes shall
        be made in U.S. Dollars, and the Notes shall be denominated in U.S.
        Dollars.

               (12) The Notes will be payable on the Stated Maturity Date in an
        amount equal to the principal amount thereof plus any unpaid interest
        accrued to the Stated Maturity Date.

               (13) The Holders of the Notes shall have no special rights in
        addition to those provided in the Indenture upon the occurrence of any
        particular events.

               (14) (A) There shall be no deletions from, modifications of or
        additions to the Events of Default with respect to the Notes set forth
        in the Indenture.

                      (B) There shall be the following additions to the
        covenants set forth in the Indenture with respect to the Notes, which
        shall be effective only for so long as any of the Notes are Outstanding:

                      Limitations On Incurrence of Debt. The Issuer will not,
               and will not permit any Subsidiary to, incur any Debt (as defined
               below), other than inter-company debt representing Debt to which
               the only parties are Spieker Properties, Inc., a Maryland
               corporation (the "General Partner"), the Issuer and any of their
               Subsidiaries (but only so long as such Debt is held solely by any
               of the General Partner, the Issuer and any Subsidiary) that is
               subordinate in right of payment to the Notes if, immediately
               after giving effect to the incurrence of such additional Debt,
               the aggregate principal amount of all outstanding Debt of the
               Issuer and its Subsidiaries on a consolidated basis is greater
               than 60% of the sum of (i) Total Assets (as defined below) as of
               the end of the calendar quarter covered in the Issuer's Annual
               Report on Form 10-K or Quarterly Report on Form 10-Q, as the case
               may be, most recently filed with the Trustee (or such reports of
               the General Partner if filed by the Issuer with the Trustee in
               lieu of filing its own reports) prior to the incurrence of such
               additional Debt and (ii) the increase in Total Assets from the
               end of such quarter including, without limitation, any increase
               in Total Assets resulting from the incurrence of such additional
               Debt (such increase, together with the Total Assets, is referred
               to as "Adjusted Total Assets").

                      In addition to the foregoing limitation on the incurrence
               of Debt, the Issuer will not, and will not permit any Subsidiary
               to, incur any Debt if the ratio of Consolidated Income Available
               for Debt Service to the Annual Service Charge (in each case as
               defined below) for the four consecutive fiscal quarters most
               recently ended prior to the date on which such additional Debt is
               to be incurred shall have been less than 1.5 to 1, on a pro forma
               basis after giving effect to the incurrence of such Debt and to
               the application of the proceeds therefrom, and calculated on the
               assumption that (i) such Debt and any other Debt incurred by the
               Issuer or its Subsidiaries since the first day of such
               four-quarter period and the application of




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               the proceeds therefrom, including to refinance other Debt, had
               occurred at the beginning of such period, (ii) the repayment or
               retirement of any other Debt by the Issuer or its Subsidiaries
               since the first day of such four-quarter period had been
               incurred, repaid or retired at the beginning of such period
               (except that, in making such computation, the amount of Debt
               under any revolving credit facility shall be computed based upon
               the average daily balance of such Debt during such period), (iii)
               the income earned on any increase in Adjusted Total Assets since
               the end of such four-quarter period had been earned, on an
               annualized basis, during such period, and (iv) in the case of any
               acquisition or disposition by the Issuer or any Subsidiary of any
               asset or group of assets since the first day of such four-quarter
               period, including, without limitation, by merger, stock purchase
               or sale, or asset purchase or sale, such acquisition or
               disposition or any related repayment of Debt had occurred as of
               the first day of such period with the appropriate adjustments
               with respect to such acquisition or disposition being included in
               such pro forma calculation.

                      In addition to the foregoing limitations on the incurrence
               of Debt, the Issuer will not, and will not permit any Subsidiary
               to, incur any Debt secured by any mortgage, lien, charge, pledge,
               encumbrance or security interest of any kind upon any of the
               property of the Issuer or any Subsidiary ("Secured Debt"),
               whether owned at the date of the Indenture or thereafter
               acquired, if, immediately after giving effect to the incurrence
               of such additional Secured Debt, the aggregate principal amount
               of all outstanding Secured Debt is greater than 40% of Adjusted
               Total Assets.

                      For purposes of the foregoing provisions regarding the
               limitation on the incurrence of Debt, Debt shall be deemed to be
               "incurred" by the Issuer or a Subsidiary whenever the Issuer and
               its Subsidiary shall create, assume, guarantee or otherwise
               become liable in respect thereof.

                      Maintenance of Total Unencumbered Assets. The Issuer is
               required to maintain Total Unencumbered Assets of not less than
               165% of the aggregate outstanding principal amount of all
               outstanding Unsecured Debt.

                      As used herein:

                      "Annual Service Charge" as of any date means the amount
               which is expensed in any 12-month period for interest on Debt of
               the Issuer and its Subsidiaries.

                      "Consolidated Income Available For Debt Service" for any
               period means Consolidated Net Income plus amounts which have been
               deducted for (a) interest on Debt of the Issuer and its
               Subsidiaries, (b) provision for taxes of the Issuer and its
               Subsidiaries based on income, (c) amortization of Debt discount,
               (d) provisions




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               for gains and losses on properties, (e) depreciation and
               amortization, (f) the effect of any noncash charge resulting from
               a change in accounting principles in determining Consolidated Net
               Income for such period and (g) amortization of deferred charges.

                      "Consolidated Net Income" for any period means the amount
               of consolidated net income (or loss) of the Issuer and its
               Subsidiaries for such period determined on a consolidated basis
               in accordance with generally accepted accounting principles.

                      "Debt" of the Issuer or any Subsidiary means any
               indebtedness of the Issuer or such Subsidiary, as applicable,
               whether or not contingent, in respect of (i) borrowed money
               evidenced by bonds, notes, debentures or similar instruments,
               (ii) indebtedness secured by any mortgage, pledge, lien, charge,
               encumbrance or any security interest existing on property owned
               by the Issuer or such Subsidiary, (iii) the reimbursement
               obligations, contingent or otherwise, in connection with any
               letters of credit actually issued or amounts representing the
               balance that constitutes an accrued expense or trade payable or
               (iv) any lease of property by the Issuer or such Subsidiary as
               lessee which is reflected in the Issuer's consolidated balance
               sheet as a capitalized lease in accordance with generally
               accepted accounting principles, in the case of items of
               indebtedness under (i) through (iii) above to the extent that any
               such items (other than letters of credit) would appear as a
               liability on the Issuer's consolidated balance sheet in
               accordance with generally accepted accounting principles, and
               also includes, to the extent not otherwise included, any
               obligation by the Issuer or such Subsidiary to be liable for, or
               to pay, as obligor, guarantor or otherwise (other than for
               purposes of collection in the ordinary course of business),
               indebtedness of another person (other than the Issuer or any
               Subsidiary).

                      "Subsidiary" means a corporation, partnership or limited
               liability company, a majority of the outstanding voting stock,
               partnership interests or membership interests, as the case may
               be, of which is owned or controlled, directly or indirectly, by
               the Issuer or by one or more other Subsidiaries of the Issuer.
               For the purposes of this definition, "voting stock" means stock
               having the voting power for the election of directors, general
               partners, managers or trustees, as the case may be, whether at
               all times or only so long as no senior class of stock has such
               voting power by reason of any contingency.

                      "Total Assets" as of any date means the sum of (i)
               Undepreciated Real Estate Assets and (ii) all other assets of the
               Issuer and its Subsidiaries on a consolidated basis determined in
               accordance with generally accepted accounting principles (but
               excluding intangibles and accounts receivable).




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                      "Total Unencumbered Assets" as of any date means the sum
               of (i) those Undepreciated Real Estate Assets which have not been
               pledged, mortgaged or otherwise encumbered by the owner thereof
               to secure Debt, excluding infrastructure assessment bonds, and
               (ii) all other assets of the Issuer and its Subsidiaries
               determined in accordance with generally accepted accounting
               principles (but excluding intangibles and accounts receivable)
               which have not been pledged, mortgaged or otherwise encumbered by
               the owner thereof to secure Debt.

                      "Undepreciated Real Estate Assets" as of any date means
               the cost (original cost plus capital improvements) of real estate
               assets of the Issuer and its Subsidiaries on such date, before
               depreciation and amortization, determined on a consolidated basis
               in accordance with generally accepted accounting principles.

                      "Unsecured Debt" as of any date means Debt which is not
               secured by any mortgage, lien, charge, pledge, encumbrance or
               security interest of any kind upon any of the properties of the
               Issuer or any Subsidiary.

                      (C) The Trustee shall not be obligated to monitor or
        confirm, on a continuing basis or otherwise, the Issuer's compliance
        with the covenants contained in this subsection or with respect to
        reports or other documents filed under the Indenture; provided, however,
        that nothing herein shall relieve the Trustee of any obligations to
        monitor the Issuer's timely delivery of all reports and certificates
        required under Sections 703 and 1005 of the Indenture and to fulfill its
        obligations under Article Six of the Indenture.

               (15) The Notes shall be issuable only as Registered Securities in
        permanent global form (without coupons). Beneficial owners of interests
        in the permanent global Notes may exchange such interests for Notes of
        like tenor or any authorized form and denomination only in the manner
        provided in Section 305 of the Indenture. DTC shall be the depository
        with respect to the permanent global Note.

               (16) The Notes shall not be issuable as Bearer Securities.

               (17) Interest on any Note shall be payable only to the Person in
        whose name that Note (or one or more predecessor Notes thereof) is
        registered at the close of business on the Regular Record Date for such
        interest.

               (18) Sections 1402 and 1403 of the Indenture shall be applicable
        to the Notes.

               (19) The Notes shall not be issuable in definitive form except
        under the circumstances described in Section 305 of the Indenture.




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               (20) Articles Sixteen and Seventeen of the Indenture shall not be
        applicable to the Notes.

               (21) The Issuer shall not pay Additional Amounts with respect to
        the Notes as contemplated by Section 1009 of the Indenture.

               (22) The Notes shall not be subordinated to any other debt of the
        Issuer, and shall constitute senior unsecured obligations of the Issuer.

        SECTION 202. FORM OF NOTE. The form of the Note is attached hereto as
Exhibit A.


                                   ARTICLE III

                                  MISCELLANEOUS

        SECTION 301. DEFINITIONS. Capitalized terms used but not defined in this
Ninth Supplemental Indenture shall have the meanings ascribed thereto in the
Indenture.

        SECTION 302. CONFIRMATION OF INDENTURE. The Indenture, as heretofore
supplemented and amended by this Ninth Supplemental Indenture, is in all
respects ratified and confirmed, and the Indenture, this Ninth Supplemental
Indenture and all indentures supplemental thereto shall be read, taken and
construed as one and the same instrument.

        SECTION 303. CONCERNING THE TRUSTEE. The Trustee assumes no duties,
responsibilities or liabilities by reason of this Ninth Supplemental Indenture
other than as set forth in the Indenture and, in carrying out its
responsibilities hereunder, shall have all of the rights, protections and
immunities which it possesses under the Indenture.

        SECTION 304. GOVERNING LAW. This Ninth Supplemental Indenture, the
Indenture and the Securities shall be governed by and construed in accordance
with the law of the State of New York.

        SECTION 305. SEPARABILITY. In case any provision in this Ninth
Supplemental Indenture shall for any reason be held to be invalid, illegal or
unenforceable, the validity, legality and enforceability of the remaining
provisions shall not in any way be affected or impaired thereby.

        SECTION 306. COUNTERPARTS. This Ninth Supplemental Indenture may be
executed in any number of counterparts each of which shall be an original, but
such counterparts shall together constitute but one and the same instrument.




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        IN WITNESS WHEREOF, the parties hereto have caused this Ninth
Supplemental Indenture to be duly executed, and the corporate seal of the
General Partner to be hereunto affixed and attested, as of the day and year
first above written.


                               SPIEKER PROPERTIES, L.P.

                               By:  Spieker Properties, Inc., as General Partner



                               By: /s/ Craig G. Vought 
                                   ---------------------------------------------
                                   Name:  Craig G. Vought
                                   Title: Executive Vice President
                                          and Chief Financial Officer
(seal)
Attest:

By:  /s/ Stuart A. Rothstein
   ----------------------------
   Name:  Stuart A. Rothstein
   Title: Assistant Secretary

                               SPIEKER PROPERTIES, INC.


                               By: /s/ Craig G. Vought 
                                   ---------------------------------------------
                                   Name:  Craig G. Vought
                                   Title: Executive Vice President
                                          and Chief Financial Officer
(seal)
Attest:

By:  /s/ Stuart A. Rothstein
   ----------------------------
   Name:  Stuart A. Rothstein
   Title: Assistant Secretary







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<PAGE>   11
                                            FIRST TRUST OF CALIFORNIA,
                                               NATIONAL ASSOCIATION, as Trustee



                                            By:   /s/ Jennifer Holder
                                                --------------------------------
                                                   Name: Jennifer Holder
                                                   Title: Vice President
Attest:

By:  /s/ Josephine Libunao
    --------------------------------
      Name: Josephine Libunao
      Title:  Assistant Vice President



                                            STATE STREET BANK AND TRUST
                                               COMPANY


                                            By:   /s/ Ruth A. Smith
                                                --------------------------------
                                                   Name: Ruth A. Smith
                                                   Title: Vice President
Attest:

By:  /s/ Carolina D. Altomare
    --------------------------------
      Name:  Carolina D. Altomare
      Title: Assistant Vice President






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<PAGE>   12
STATE OF   California   )
COUNTY OF  San Mateo    ) ss.:

        On the 26th day of September, 1997, before me personally came Craig G.
Vought to me known, who, being by me duly sworn, did depose and say that he is
the EVP and CFO of Spieker Properties, Inc., one of the entities described in
and which executed the above instrument; that he knows the corporate seal of
said corporation; that the seal affixed to the said instrument is such corporate
seal; that it was so affixed by authority of the corporation, and that he signed
his name thereto by like authority.




                                            /s/ Julie L. Bartlow
                                            -------------------------------

        [Seal]






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