88 ASSOCIATION OF ORGANISMS—THE WEB OF LIFE 
passes below into a heart-shaped sticky knob (vostellum) that 
projects into the cavity of the stigma. If now a fly alights on the 
footstool and begins to lick up the nectar from the stigma, its 
head will come into contact with the rostellum, and on leaving the 
flower it will carry away the pollinia, which very quickly bend 
forwards. When the fly visits another flower and thrusts its head 
into the stigma, the sticky surface of this will catch and retain the 
pollinia, another pair of which will become attached to the head of 
the insect, to be carried on in their turn to another blossom. 
The Lesser Butterfly Orchis (Hadenaria bifolia, fig. 1080) is 
a much smaller form native to Britain, and cross-pollinated by 
Hawk - Moths. A number of whitish very fragrant flowers are 
borne upon a long upright stalk, and there is here no platform 
for the arriving guests, as these sip nectar without having to 
alight. The nectar is contained in a slender spur, the length of 
which corresponds to that of the unrolled proboscis of the moth. 
As before, the departing guest carries away the two pollinia, 
which then bend downwards, and converge together into the exact 
position necessary to ensure their striking the stigma of the next 
flower visited. In regard to these movements, and the somewhat 
different ones made by the pollinia of other species, Darwin re- 
marks (in Fert:ization of Orchids):—“ A poet might imagine that 
whilst the pollinia were borne through the air from flower to 
flower, adhering to an insect’s body, they voluntarily and eagerly 
placed themselves in that exact position, in which alone they could 
hope to gain their wish and perpetuate their race”. To this same 
book of Darwin’s are referred those readers who desire further 
particulars regarding Orchids in the present connection. 
The different species of Honeysuckle (Louzcera, fig. 1080) are 
also ‘“moth-flowers”, and exhibit three of the leading features 
just detailed for the Butterfly Orchis, z.e. absence of an alighting 
platform, pale colour, and marked fragrance. But, as in most 
flowers except Orchids, the pollen is dust-like, and not aggregated 
into pollinia. 
Insects are not the only animals by which cross-pollination 
is brought about, for in some instances this work appears to be 
discharged by Snails and Slugs, Birds, or Mammals. In our two 
native species of Golden Saxifrage (Chrysosplenium), snails and 
slugs are said to be the agents. These plants live in damp places, 
and possess groups of small greenish-yellow flowers, over which 
