54 THE FERTILISATION OF FLOWERS. [CHAP. 
parts of the flower are highly sensitive, and when 
touched by a bee convey the impression to the pol- 
linia which ruptures the confining membrane and 
hurls the pollinia at the bee, striking it and adhering 
to it where, on visiting another flower, they come in 
contact with the stigma. 
The various methods by which fertilisation is 
effected in the Orchids is in fact more marvellous 
than in any other genus. “The complication and 
ingenuity of these contrivances almost exceed belief. 
‘Moth-traps and spring-guns set on these grounds’ 
might be the motto of the Orchids. There are baits 
to tempt the nectar-loving Lepidoptera with rich 
odours exhaled by night and lustrous colours to shine 
by day; there are channels of approach along which 
they are surely guided, so as to compel them to pass 
by certain spots; there are adhesive plastérs nicely 
adjusted to fit their probosces or to catch their 
brows; there are hair-triggers carefully set in their 
necessary path, communicating with explosive shells 
which project the pollen stalks with unerring aim 
upon their bodies. There are, in short, an infini- 
tude of adjustments, for an idea of which I must 
refer my readers to Mr. Darwin’s inimitable powers 
of observation and description—adjustments all con- 
trived so as to secure the accurate conveyance of the 
pollen of the one flower to its precise destination in 
the structure of another.” * 
In the common yellow Flag (/rzs pseudacorus) ‘Sere 
of the perianth segments are large and arched over, 
so as to form a platform, similar to the /abellum of 
* Duke of Argyll, ‘‘ Reign of Law,” p. 38. 
