Page:On the Various Contrivances by Which British and Foreign Orchids are Fertilised by Insects, and on the Good Effects of Intercrossing.djvu/24

 The structure of this flower resembles in most points that of the last species; but, owing to the upturning of the labellum, it is rendered almost tubular. The naked glands are minute, but elongated and approximate. The stigmatic surfaces are partly lateral and divergent. The nectary is short, and full of nectar. Minute as the flowers are, they seem highly attractive to insects: of the eighteen lower flowers in one spike, ten had both pollinia, and seven had one, removed; in some other and older spikes all the pollinia had been removed, except from two or three flowers at the summit.

Habenaria chlorantha

The pollinia of the Large Butterfly Orchis differ considerably from those of the species hitherto mentioned. The two anther-cells are separated from each other by a wide space of connective membrane; the pollinia slope backwards (Fig. XI.), and the viscid discs are brought out in advance of the stigmatic surface, and front each other. In relation to this position of the discs, the caudicles and pollen-masses are much elongated. The viscid disc is circular, and, in the early bud, consists of a mass of cells, of which the exterior layers (answering to the lip or pouch in Orchis) resolve themselves into adhesive matter. This matter has the property of remaining adhesive for at least twenty-four hours after the pollinium has been removed from its cell. The disc, externally covered with a thick layer of adhesive matter (see Sect. C, which stands so that the layer of viscid matter is below), is produced on its opposite and embedded side into a short drum-like pedicel. This pedicel is continuous with the membranous portion of the disc, and is formed of the same tissue. At the embedded end of the pedicel, the caudicle of the pollinium is attached in a transverse direction, and its extremity is prolonged, as a bent rudimentary tail, just beyond the drum. The caudicle is thus united to the viscid disc in a very different manner, and in a plane at right angles, to what occurs in other British Orchids. In the short drum-like pedicel, we see a small development of the long pedicel of the rostellum, which in many exotic Vandee is so conspicuous, and which connects the viscid disc with the true caudicle of the pollinium.