404 



ANGIOSPERMAEMONOCOTYLEDONES 



2621. H. hyperborea R. Br. ( = Platanthera hyperborea Ltndl.). Warming 

 describes the flowers of this species as possessing a vanilla odour, and Darwin states 

 that they are regularly self-fertilized. 



2622. H. viridis R. Br. (=Peristylus viridis Ltndl). (Darwin, op. cit, 43, 63, 

 255 ; Herm. Miiller, * Alpenblumen,' p. 72.) 



Visitors. Probably small moths. 



819. Platanthera Rich. 



2623. P. chlorantha Cust. {=V.moniz.na. Rekhb./.; Habenaria chlorantha 

 Bab. ; and H. bifolia R. Br., according to the Index Kewensis). (Darwin, ' Orchids,' 

 p. 69 ; Herm. Miiller, * Alpenblumen,' p. 72 ; MacLeod, Bot. Jaarb. Dodonaea, 

 Ghent, v, 1893, p. 323; Kirchner, 'Flora v. Stuttgart,' p. 171.) The almost 



odourless, green flowers of this species are larger than 

 those of Habenaria hyperborea, and the spur is 23-43 mm. 

 long ; very rarely, however, flowers entirely without a spur 

 occur. The caudicles of the pollinia are united by small, 

 drum-shaped expansions to the disks, and as these are 

 situated more deeply in the entrance to the spur, the 

 pollinia attach themselves to the eyes of visitors. 



Visitors. Dar^vin observed 2 moths a Plusia sp., 

 carrying a poUinium on the edge of one eye ; and 

 Mamestra dentina Esp., with a pollinium on one eye. 



820. Ophrys L. 



Partly fly flowers. Frequently automatic self-pol- 

 lination. Inflorescences unilateral in consequence ofj 

 twisting of the ovaries. 



2624. O. muscifera Huds. (=0. myodes /acq.). 

 (Darwin, op. cit., p. 45 ; Herm. Miiller, ' Weit. Beob.,' I, 

 pp. 285-91 ; Kirchner, op. cit., p. 172.) The elongated, 

 velvety labellum in this species is blackish-purple in 

 colour, marked with an almost square, glabrous, pale- 

 bluish central patch ; it secretes small drops of nectar 

 down the middle in a longitudinal furrow for a short 

 time immediately after the flower opens ; later on there 

 is merely a thin, shining, damp layer, which disappears 

 immediately. A button-shaped process, with an almost 

 metallic gleam, situated on each side of the base of the 



labellum, serves as a further attraction. It seems, therefore, that the fly flower is 



a deceptive one adapted to the visits of carrion-flies. 



Visitors. Herm. Miiller observed Sarcophaga ; insect-visits, however, are so 



few, that the flowers generally remain unpollinated. The same observer also saw 



a fossorial wasp (Gorytes mystaceus Z.) on a flower, without obtaining anything, 



however, or removing pollinia. 



Fig. 373. Platanthera chlo- 

 rantha, Cust. (after Pfitzer). A. 

 A flower, seen directly from the 

 front. ////, lateral petals ; pnt, 

 labellom ; .;/ si, lateral sepals ; 

 stH, upper sepal ; sp, spur. B. 

 A pollinium, seen from the side. 



