, 1875-03-21

ing OF flowers has reference to tho habits Of in
secta-shat they fold their petals and rest durinl
the hours that the peculiar species Of insect
which frequent them are quiet. It Ia certai1
thu. ~lnd-fertilized flowers do not sleep. Il il
also fact that some OF those flowers that invit'
insects BY their perfume exilale it at par:icula!
hours thus. Lyclnis uespertina gives OF it
t odor in the evening. But this is one Of th'
questions connected with tho fertilization O.
flowers that still remain to be settled.
Recurring to the subject Of crcss.f fertilization
wa find that there arc three principal method:
by which the III effects Of breeding in-and-in are
prevented. Firat, in numerous species. the
atamens and pis:ils arc situated in different ho"'
ers. Second In many instances, where TIT
! stamans aud pistl are in the Same flower, they
do not mature simultaneously, therefore the
pollen cannot fertil,ze the stigma Thirdly,
there ere certain species which have two or more
kinds Of fowere Ill alike provided with stamena
and pistil, but differing in the relative position
Of these organs, which are go placed as to favor
the transfereuce OF the pollen from one flower to
the stigma Of another. IN piants which are not
| in ;luded ID these categoues there are minor
notifications which tend to secure csoss-fer1ll-
ization, and We may conclude with Darwin that
no plant invariably fertihzes itself.
Bat let rs W7ito, in a few examples, the method
BY which insects act as the marriage priests Of the
| the fowera. Take the arun. known by the Ea-
g!ish names Of " wi1d-turnip, aud '.Jack in tie
pulpit" In this flower there ia central n1llar
! envclopod in green or purple, long-pointed
Leaf. Tbe base OF the pilnr is encircled By zowa
| OF etigmaa, and, 3 little higher, by rows Of
anthers or pollen cases. The flower cannot fer
hize itself, because the st,gm7s ripen before the
snthers aud by the time the pollen ia ahed
| they are withered The Wind cannot reach the
pollen and carry it from flower to flower, and so
1t drops to tho bottom Of the blossom as it fails
from the anthers. But small insects, attracted
by the colots Of the leaf and tho pillar and by
the prospsct OF honey which these hold
ont, creep DOM into the tube OF the
flower, which has a fringe Of hairs turning down.
wards, allowing their entrance, but forbidding
their exit. They thelefore find themselves
prisoners, and buzz about in lively manner,
kicking up rhe dust OF the pollen and getting
Themselves we'll coated with it. As each stigma
natures it exudes O. drop Of nectar, and on this
the captives feed during thelr Imprisonment.
After the anthers have t.pened and shed their
contents, tho hairs which deba11ed the exit of
the insects gradually uithcr aw2y and they are
set free, bearing burden OF pollen along with
them Those OF .hem which visit q second
arum cannot fail To depos,t a norton ~ TIM
pollen st1herino tn thnn m its stv,noa and tina
tia work of fert,l,zinP the fouar In dona II
would ssan that these insects won1d mt oat
trapped = eecond time. vet sonet;me. noora TIM,
a hundrad of them ara fonnd IL a x;nc,a .x,,,
and the aneciex oe,aral1v haer. .b,nd,,+ saaA
in it's season.
fill rnora cnrione :. tb. rosn,sr :, v.,;,,
varion. orchida haon;1a ;nsacta ;nto +hsi~
sarvico. Ne.r1v all tha noamhara ~ +b;a y.r,;,v
demand upou THAR v;need visi.ora fo- fer.;1;7s.
hon. Some relv exclnsivc]v nnon vasn. otbare
unnn rotba md bntteraiea ,nd othara .oa;,
nnon baes diea etc Tha NOLAN in ,noxt
orchids ia done up in tvo little bundlaa tied
together bvxfne elastic threads. anl each faeten-
ed to tina upner end of a stalk In anna casps
tbe lover and of the atalk ter1ninates in ronnd
disk that is verv sticky. In the greater green
o,chis (Ha1ernaria orbicu,ata) the enther which
holds the two pollen maases is in the cantre of
the flower. and the two sticky disks at the oppo |
site ends Of the stalks diveree so ss to admit the
head Of an inject between them. |
When the bee OF butterfly comes to eip nectsr
from the flower. it ia Obliged to thrnst ita hand
between the stalks to find tha oridca thronrh /
which it can suck the honey held in the long |
nectary In its efforts to drain the houey-tube |
its head hits one OF Roth OF the sticky disks which
xdhers to it, 20 that when it departs it USUALLY
bears away the whole pollnn disk, stalk. and ALL +
1t first the stalk points upwards sod forwards in
such way that it the insect were on the instant
to thrust its head into another flower the pollen
would fail to hit the stigma But this accident
is provided against. In from ten to thirty SEC
,nds after the pollen has been detsched from
he flower, tho stalk bends down Is il On Joint,
bringing the little vaxeu uaass in sxactly the no.
r. nm In hi, fhe stipma nf fha Dext archia via |
- :--. ~.
teo- Inc sngma ls covered with flscio sub
tthuce which catches mo1e or less of the pollen
,-,no,t ir conts,+ vjrb !, and tbrs ~.
:,
>rchiA in fArtillZod- Essentially the aarpo
}roceaH Ia ropexted in the fertilization
- ....~ - ~. ...t;5. r..x:. -. |
u many OF tao orcnloa. OI"io oas
il1ed who1e volume with descrin- |
;o,s ~ I'm di9ara,+ ,,a,hot,x hv zb;oh -,
~.
peclea OF tQ15 CoosI soEuaaE 1anuy arc 1eltli- |
,oa II ono avtraord,n.r r.ao tho+ ~ tha |
LOU - oae ease' ~a4& " sn0
N~~4'S"'"'' 'ao FoA~A ~ "A ~ Fos-' ".o
, in it: quest s for ess hsss d DOES Is. 10: :nst
w o1oAoto "0a' "01" su' Ao"S4 ~ ~. ~etoA11s
brow The p0l6U 1t f1B Ut[lH c8If1bT WHICH 18 10 |