i6 NATIVE BRITISH ORCHIDACE^ 



pollinium. The two pollinia, erect when first withdrawn, move downwards till they 

 point forwards horizontally, the correct position for ensuring contact with the stigma. 

 This movement is timed, not being completed soon enough to admit of contact with 

 the stigma of flowers on the same spike, but the right position being attained by the 

 time the next spike is reached. 



The small honey-scented Herminium has slightly distant viscidia, specialised to fit 

 on the joint of the leg of very small insects, only one pollinium being removed at a 

 time. Caloglosstim has still more distant viscidia, with a ridge down the lip, compelling 

 insects to enter on one side and remove one pollinium at a time. The downward 

 diverging anther-cells foreshadow those of P/atanthera chlorantha, to which genus it 

 was assigned by Lindley. Platanthera is organised to attract Lepidoptera by free honey 

 in a long spur, and is remarkable for the large naked viscidia facing each other, and 

 thus becoming attached to the sides and not to the front of the head or proboscis 

 of moths. It is the climax of a long series of very ancient forms, for several species 

 occur in N. America. 



Gywiiadenia also secretes free honey in its spur, G. compsea catering (like Platanthera) 

 for Lepidoptera with a long proboscis, and G. odoratissima and G. a/bida for short- 

 tongued insects. It is remarkable for the lateral position of the separate stigmas on 

 side-wings of the 3-lobed column, instead of in the centre of the flower as in all our 

 other orchids, except Herminium in which separation is incomplete, there being two 

 transverse stigmatic surfaces meeting by their points in the middle, and Anacamptis 

 and Neotinea, which are really Gymnadenia which have evolved the rostellar pouch, 

 viscidia, and tubers of Orchis. Anacamptis appears to be descended from G. conopsea 

 (to which it bears an extraordinary likeness) or some extinct collateral species, and 

 Neotinea perhaps from G. alhida or some nearly allied collateral. For the reasons 

 supporting this conclusion see below, under Serapiadince. Darwin considered that in 

 no other plant was the correlation of the various parts with the habits of such widely 

 remote organisms (Lepidoptera) more complete than in Anacamptis. It is of com- 

 paratively recent origin, extending only to the Caucasus, Asia Minor, and N. Africa, 

 but not America. 



In Orchis no free nectar is secreted, and the spur is dry, which suggested to Delpino 

 degeneration and incipient extinction. A store of potable liquid, however, exists 

 between the walls of the spur, the inner skin of which is easily pierced. Delpino 

 maintained that this was not honey, but sap. Whatever its nature, it acts as a powerful 

 attraction, for Orchis has not only evolved the largest number of species (75) of any 

 genus of the Old World, but these transcend all others in abundance. The genus is 

 apparently absent from America, Orchis rottmdijolia Pursh. and O. spectahilis L., 



simple in the Neottiea:, Malaxidece, etc., and we do not come to cases of two viscidia till we reach the 

 most highly evolved tribe of all, the Ophrydea:. 



