124 NATIVE BRITISH ORCHIDACE^ 



boggy ground, usually growing in Sphagnum. In the plains Herminium rarely seeds, 

 but increases by the supplementary tubers.' 



Habitat. Chalk downs, mountain pastures, grassy hills, meadows, "dunes, plains, 

 sub-alpine marshes", usually on calcareous, but sometimes on clayey damp soils 

 (Camus). It usually occurs in colonies, owing to the production of additional tubers. 

 It ascends to 5000 ft. in Switzerland and Savoy, and 8000 ft. in the Caucasus, according 

 to Sclilechter. Flowers June to July. Rare in Britain, and very local. 



Distribution. Southern and Eastern England, Kent, Surrey, Sussex, Hants., 

 Dorset, Somerset, Gloucester, Wilts., Bucks., Beds., Northants., Cambridge, Suffolk, 

 Norfolk, Oxford (Sowerby, £.B.). Most of Europe, from Norway and Sweden to 

 the Mediterranean, Caucasus, Himalayas, throughout Siberia in both dry and damp 

 meadows (Reich.), Yunnan, Eastern Mongolia (Camus). 



Herminium monorchis R. Br. in Ait. Hort. Kew. ed. 2, v, 191 (1813). Ophrys 

 MONORCHis L., Sp. pi. ed. i, p. 947 (i753)- Orchis monorchis All. Epi- 

 PACTis MONORCHIS Schmidt. Herminium clandestinum Grenier et 

 Godron, F/. 'France (1856). 



Fertilisation. The flowers, though very small and inconspicuous, emit a strong 



honey-Hke odour, and are highly attractive to minute insects not as a rule exceeding 



one-twentieth of an inch in length. They are visited by very small Hymenoptera, the 



most frequent of which is Tetrastkhm diaphantm, by flies, and by Malthodes hrevicollis, 



a beetle.' Hermann Miiller saw them visited in the Alps by small Braconidas and 



Pteromalids, parasitic Hymenoptera with similar habits to Ichneumonidae.3 They 



enter the drooping flower at a corner between the lip and a petal, crawling in with 



their backs to the lip, and inserting their heads and forelegs into the basal cup. In 



doing so the projecting joint formed by the coxa and the femur of one of the front 



legs readily slips into the hollow base of the viscid gland, the adhesive matter of the 



latter gluing it firmly to the elbow or to the surface of the femur. The polHnium 



then moves downwards till it projects just beyond the tibia. The insect, on entering 



another flower, can hardly fail to deposit pollen on the stigma, which lies just beneath 



the viscid gland on either side. The extraordinary shape of this gland is therefore 



clearly an adaptation to enable it to fit like a cap on the projecting joint of the insect's 



foreleg. 



I Camus, Icon. p. 564. ' Darwin, ¥ert. Orch. ed. 2, p. 61. 



3 Alpenhlumen, p. 72 (1881). 



