80 MR. DARWIN ON THE EXISTENCE OF TWO FORMS 
and pollen will adhere to different parts of an insect’s body, and 
will generally be brushed off.by the stigmas of corresponding 
height, to which stigmas each kind of pollen is adapted. In this 
species, the corolla is flatter, and in the one form the stigmas and 
in the other form the anthers stand at some height above the 
mouth of the corolla*. These longer stigmas and longer stamens 
do not diverge greatly ; hence insects, especially rather small ones, 
will not insert their proboscides between the stigmas or between 
the anthers, but will strike against them, at nearly right angles, 
with the backs of their head or thorax. Now, in the long-styled 
flowers of L. perenne, if each stigma had not rotated on its axis, 
insects in visiting them would have struck their heads against the 
backs of the stigmas; as it is, they strike against the papillous 
fronts of the stigmas, and, their heads being already charged with 
the proper coherent pollen from the stamens of corresponding 
height borne by the flowers of the other form, fertilization is per- 
fectly effected. 
Thus we can understand the meaning of the torsion of the 
styles in the long-styled flowers alone, as well as their divergence 
in the short-styled flowers. 
One other point is worth a passing notice. In botanical works 
many flowers are said to be fertilized in the bud. This rests 
solely, as far as I ean discover, on the anthers opening in the bud ; 
no evidence is adduced that the stigma is at this period mature, 
or that, if then penetrated by pollen-tubes, it is not subsequently, 
after the expansion of the flower, acted on by pollen brought from 
other flowers. In the case of Cephalanthera grandiflora Y have 
shownt by experiment that insufficient precocious self-fertiliza- 
tion, together with subsequent full fertilization, is the regular 
course of events. The belief that flowers of any plant are habitu- 
ally fertilized in the bud, or are perpetually self-fertilized, is à 
most effectual bar to really understanding their structure. lam 
far from wishing to say that some flowers, in certain seasons, are 
not fertilized in the bud: I have reason to believe that some 
flowers are frequently fertilized without expanding ; but my ob- 
servations lead me to disbelieve that this is ever the invariable 
* T neglected to get drawings made from fresh flowers of the two forms. 
Mr. Fitch has made the above sketch of a long-styled flower from dried speci- 
mens and published engravings : his well-known skill ensures accuracy in the 
proportional size of the parts ; and I believe their relative position is true. 
+ Fertilization of Orchids, p. 108. 
