126 NATIVE BRITISH ORCHIDACE^ 



broader than long, cells club-shaped, brownish, toucliing at apex, divergent below. 

 Pollinia pale greenish yeUow, together with the straight ribbon-shaped caudicle 

 just under 2 mm. long. Viscidia two, oval, separated by a thicliened arched ridge, 

 each enclosed in a tender skin. Stigma kidney-shaped, on back of chamber at base 

 of hp, bordered by dark side-lines. 



Easily recognised by the green flowers with aknost globular green or red-brown 

 heknet, and the strap-shaped often red-edged lip, ending in three teeth, the middle 

 one shorter and broader than the side ones. Rarely more than 8 in. (20 cm.) taU in 

 Britain. Varies but httle except in the very variable length of the bracts, sometimes 

 short (var. microbracteatum Schur), sometimes considerably exceeding the flowers (var. 

 hracteatum K. Richt.), sometimes very long and leaf-hke (var. macrobracteatum Schur), 

 and in the amount of red-brown with wliich the flowers are suff"used. Reichenbach 

 states that it is the iirst orcliid to reappear in fields when turned into meadows, and 

 holds its own tenaciously in meadows turned into woods, which perhaps explains 

 its presence in such an unusual habitat. It sometimes remains underground for two 

 or tliree years and then reappears in plenty. The name Frog Orchid appears to be 

 rather fanciful, but the side-view of the flower is sometimes faintly suggestive of a 

 frog. PI. C, fig. 3, shows a specimen of the var. bracteatum from near Mold, N. Wales, 

 photographed by Col. C. T. Green, June 4th, 1927. 



Habitat. Moist or dry pastures, chalk downs, grassy hillsides especially on 

 calcareous soil, also (rarely) in woods, and occasionally on sandhills. Flowers June 



to August. 



Distribution. Frequent in Northern England, Scotland and Ireland, where it 

 occurs at sea-level in N. Donegal and Kerry, and ascends to 1000 ft. (349 m.) in 

 Derry, Dublin and Clare. Not so frequent in Southern England and Wales. Most 

 of Europe, from Iceland and Scandinavia to Spain, Italy and Northern Balkans; 

 Mid- and S. Russia, Caucasus, Asia Minor, Siberia, China, N. America. 



Fertilisation. The spur contains free nectar, wliich can be seen to rise on pressure. 

 Just below the viscid disc at the foot of each poUinium there is also a shallow depression 

 ghstening with nectar. The ridge down the middle of the lip causes an insect to crawl 

 up on one or other side of it, and thus guides it to the exposed drop of nectar on 

 that side. In licking tliis up it is almost sure to touch the viscid disc immediately 

 above it, and carry off the polhnium attached to its head. It then goes to the small 

 orifice leading to the spur, where it finds ample provision of nectar. The pollinium 

 moves downwards very slowly, and does not reach the position in wliich it can touch 

 the stigma for about 20 minutes or more. An insect can thus visit all the flowers open 

 on the spike, and perhaps some of those on another plant, without depositing any of 

 the pollen on their stigmas, but when once the pollinium has moved down to the 

 right position, some of its pollen will be left on each stigma subsequently visited. 



