80 MB. DAEWIK OJf THE EXISTElfCE Or TWO EOEMS 



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. JSTow, in the long-styled 

 .flowers oi L. perenne, if each stigma had not rotated on its axis, 

 insects in visiting them would have struck their heads against the 

 backs of tlio 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 efiected. 



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 can 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 Ceplialanthera graniiflora I have 

 shown t by experiment that insufiicient 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 a 

 most effectual bar to really understanding their structure. I am 

 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 



* I 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 engrarings : his well-known skill ensures accuracy in the 

 proportional size of the parts ; and I believe their relative position is true. 



+ Fertilization of Orcliids, p. 108. 



