ORCHIDEAE 



399 



2613. O. pyramidalis L. (=Anacamptis pyramidalis Rich). (Darwin, op. cit., 

 pp. 16-25; Herm. Muller. 'Fertilisation,' p. 534; Kirchner, 'Flora v. Stuttgart,' 

 p. 169.) The mechanism of the carmine-red or flesh-coloured, fragrant flowers of 

 this species agrees with that of Orchis. They secrete free nectar, however, which is 

 concealed in such a narrow spur that it is only accessible to the thin proboscis of 

 a Lepidopterid. Two longitudinal ridges on the labellum serve as guides. There is 

 a circular stigmatic surface situated on each side of the rostellum. The gland 

 containing mucilage is saddle-shaped, corresponding to the shape of the Lepidopterid 

 proboscis, to which the pollinia will chng. When the epidermis of the rostellum has 

 been torn by the proboscis of a lepidopterid visitor, the gland, with the two pollinia, 

 adheres so firmly to this organ as to surround it when the mucilage dries. The two 



Fig. 366. Orchts tistulata, L. (after Herm. Muller). A. Flower, seen directly from the front (X 7). 

 B. Do., in longitudinal section. C. Excised labellum, seen from above. D. Reproductive organs 

 and root of labellum, seen directly from the front (x 16). E. A pollinium attached to a needle (forward 

 and downward bending completed) ( X 35). F. Older flower, seen from the side ( X 7). Reference letters 

 as Fig. 365. 



pollinia now bend simultaneously outwards and forwards, so that when the insect 

 carrying them visits another flower of this species they are pressed directly on to the 

 two stigmatic surfaces. 



Visitors. Darwin observed 23 species of butterflies and moths with pollinia 

 attached to their proboscis. 



2614. O. hircina Crantz (=Himantoglossum hircinum Spreng., and Sartyrium 

 hircinum Z.). (Hildebrand, Bot. Ztg., Leipzig, xxxii, 1874, p. 748.) The inner side 

 of the white helmet in the (?) bee flowers of this species is purple-red in colour with 



