rERTILIZATION IN PLANTS. 
431 
was led to adopt tlie hypotliesis tliat here was the nectar of 
which he was in search_, confined in a chamber between the two 
membranes of the nectary^ and that the lax inner membrane 
might be penetrated by insects^ and thus a supply of fluid ob- 
tained. Further, that the delay caused by the necessity of first 
puncturing the membrane, would detain the insect longer than 
otherwise, and thus unable the discs of the pollinia to become 
more securely attached to the head or back of the insect before 
leaving the flowers. 
If this relation [he concludes] on the one hand between the viscid matter 
requiring some little time to set hard, and the nectar being so lodged that 
moths are delayed in getting it ; and, on the other hand, between the viscid 
matter being at first as viscid as ever it will become and the nectar lying all 
ready for rapid suction, be accidental, it is a fortunate accident for the plant. 
If not accidental, and I cannot believe it to be accidental, what a singular 
case of adaptation ! 
A singular exception to the general rule in the Orchids ex- 
amined, was the Bee Orchis {Ojphrys ajpifera), for, in this 
instance, self-fertilization appears to have been provided for. 
There are two pouched projections of the rostellum, as in many 
other species. The caudicles to which the pollen-masses are 
attached, are very long, thin, and flexible, and not possessed 
of sufficient rigidity to stand upright. The upper ends are 
curved forwards, and the masses of pollen directly overhang 
the stigmatic surface. When the flowers open, the pollen cells 
rupture, and the masses of pollen soon drop forwards sus- 
pended by the slight vibrating caudicle just opposite to the 
stigma, so that the slightest puff of wind sets them in motion ; 
and as they oscillate, the pollen touches against the viscid 
stigma, and some grains are left adhering, whereby impreg- 
nation is effected. 
It is impossible to doubt that these points of structure and function, which 
occur in no other British orchid, are specially adapted for self-fertilization. 
One other illustration from the British Orchids must be the 
last to which we can refer in detail. This species is the Ladies^ 
Tresses {Spiranthes auhimnalis) , The long, thin, flat rostellum 
projects from the summit of the stigma (fig. 8 r). The disc is 
boat-shaped, standing vertically on its stem, imbedded in a 
fork of the rostellum (fig. 9) . This little boat is filled with a thick 
adhesive fluid, which turns brown, and becomes hard on ex- 
posure to the air ; the membrane of the rostellum folds over 
the boat, and covers it like a deck. A longitudinal furrow 
extends over the middle of the boat, which splits through its’ 
whole length on being touched gently with a needle, and a little 
adhesive fluid exudes. After this splitting, the boat becomes 
