Page:Darwin - The various contrivances by which orchids are fertilized by insects (1877).djvu/181

In Calanthe masuca and the hybrid C. dominii the structure is very different to what it is in most other Vandeæ. We here have two oval, pit-like stigmas on each side of the rostellum (fig. 26). The viscid disc is oval (fig. B), and has no pedicel, but eight masses of pollen are attached to it by very short and

Fig. 26.

Calanthe masuca.

s s.p. pollen-masses.

s s. the two stigmas.

s s.n. mouth of nectary.

s s.l. labellum.

s s.d. viscid disc.

s s.cl. in fig. C, clinandrum the pollen-masses being removed.

A. Flower viewed from above, with the anther-case removed, showing the eight pollen-masses in their proper position within the clinandrum. All the sepals and petals have been cut away except the labellum.

B. Pollen-masses attached to the viscid disc, seen from the under side.

C. Flower in same position as in A, but with the disc and pollen-masses removed, and now showing the deeply notched rostellum and the empty clinandrum in which the pollen masses lay. Within the left-hand stigma two pollen-masses may be seen adhering to its viscid surface.

easily ruptured caudicles. These pollen-masses radiate from the disc like the leaves of a fan. The rostellum is broad, and its sides slope on each side towards the lateral pit-like stigmas. When the disc is removed the rostellum is seen (fig. C) to be deeply notched in the middle. The labellum is united to the column almost up to its summit, leaving a passage (n, A) to