OPHRYDE^— GYMN AD ENIIN^— PL AT ANTHER A 135 



secrete nectar. Fruiting capsule spindle-shaped with tliree acute angles, brown, 

 shining, erect, ± 2 cm. long, dehiscing along the narrow rib in the middle of each 

 of the three sides. 



P. bifolia and P. chlorantha are so similar in general appearance as to have been 

 frequently regarded as forms of one species. They are easily distinguished as a rule 

 by the anther-cells, which are erect, parallel and close together in P. bifolia, sloping 

 backward, divergent and much wider apart at the base than at the summit in P. chlo- 

 rantha. In the latter the stem is taller, stouter (diameter about 5 mm. or more in 

 well-grown plants), the spike broader (owing to the longer ovaries), the flowers 

 rather larger, often much more tinged with green (especially when first open), only 

 scented by night as a rule, and the spur is longer, stouter, often flattened and club- 

 shaped at tip, curved and usually horizontal or directed downwards. In P. bifolia the 

 diameter of the stem is 2-3 mm., the ovaries are shorter, the spike narrower, flowers 

 rather smaller, purer white, scented by day, and the spur is very slender, nearly 

 straight and horizontal. 



P. chlorantha P. bifolia 



Anther. Wide open, flat, truncate, grooved Folded forward in a O, ridged at back, cells 



at back, cells 3-4! mm. long, divergent, 2-z| mm. long, parallel, close together, 



leaning back. erect. 



Pollinia. Total length 4 mm., caudicle longer Total length 2 mm., caudicle shorter than 



than pollen-mass. pollen-mass, much shorter than in 



chlorantha. 

 Viscid discs large, circular, ± 4 mm. apart, Smaller, oval, drum-like pedicel replaced 



with dr\mi-like pedicel, becoming attached by a longitudinal ridge, only i mm. or 



to the side of the head of large moths less apart, becoming attached to the base 



(often to the eye). of the proboscis of smaller moths. 



Habitat. Clearings and borders of woods, hillsides, grassy slopes, less frequently 

 in marshy ground and moist pastures. Flowers June to July, according to Camus 

 {Icon. p. 406) about 20 days before P. bifolia. 



Distribution. Throughout Great Britain and Ireland, found up to 1000 ft. eleva- 

 tion in Derry. Locally abtmdant, but not common as a rule. 

 Lusus ecalcarata. Without spur. Berks.' 



Europe: Scandinavia and Russia (except in the extreme north) to the Mediter- 

 ranean and its islands. Siberia, Caucasus, China, Japan. 



Platanthera chlorantha Rchb. p. (Mossl. Handh. ir, 1565 (1828)). 

 Orchis BiFOLiAyL. (1753). Platanthera bifolia Rich. (1818). Orchis 

 CHLORANTHA Custer (1827). O. viRESCENS Gaud. (i 829). O. ochroleuca 

 Rchb. p. (1830). Habenaria bifolia ^ Hooker (1830). H. chlorantha 

 Bab. (1837). Platanthera virescens Koch (1849). P. Montana Rchb. f. 

 (1852). Habenaria CHLOROLEUCA Ridley. H. virescens Dr. 



' B.E.C. p. 399 (1921). 



