566 PART III. — THE CLASSIFICATION OF PLANTS. 



The genera of Orchidacese are so numerous and so diverse that it is impos- 

 sible to give more than a summary of those which are British. 



DiANDR^ : two fertile stamens, belonging to the inner whorl : all three lobes 

 of the stigma are susceptible of pollination : pollen-grains cohering but slightly. 



Fam. 1. Cypripediince. Cypripedium Calceolus, the Lady's Slipper, now 

 very rare, occurs in woods in the north of England : it has a creeping rhizome 

 and broad ovate leaves : the perianth is of a reddish-brown colour, except the 

 labellum which is yellow and forms a shoe-like sac (Figs. 369, 372). 



Monandry : one fertile stamen, the anterior, belonging to the outer whorl : 

 only the two lateral lobes of the stigma are susceptible of pollination ; the 

 anterior lobe is rudimentary, or is developed as the rostellum : pollen-grains 

 coherent into pollinia. 



Fam. 2. Ophrydince : anther short and broad ; the waxy pollinia are basit- 

 onous ; a rostellum, forming retinacula to which the caudicles of the pollinia 

 adhere. 



To the sub-family Serapiadece, which is characterised by the short gynos- 

 temium and the erect anther, belong the genera Ophrys, Orchis, and Aceras. 

 In Ophrys there are two distinct bursiculae and retinacula, and the pollinia 

 remain distinct : the flowers resemble insects : 0. apifera the Bee Orchis, O. 

 aranifera the Sj)ider Orchis, and 0. muscifera the Fly Orchis, occur in chalk 

 pastures. In Orchis there is but one bursicula, but there are two retinacula, so 

 the pollinia may be removed separately, and the labellum is spurred : Orchis 

 Morio, mascula, and militaris, hsLve round or oval tubers ; whilst 0. latifolia, 

 maculata, and pyramidalis have palmate tubers. In Aceras {Aceras anthropo- 

 phora is the green Man-Orchis) the 3-lobed lip is not spurred, and there is but 

 one retinaculum. 



To the sub-family Gymnadeniece, characterised by the absence of a bursicula, 

 and consequently bare retinacula, belong the British genera Gymnadenia, 

 Habenaria, Neotinea, Herminium (as also other interesting European genera, 

 such as ChamaBorchis and Nigritella). In Gymnadenia {G. Conopsea, the 

 fragrant Orchis) the retinacula are contiguous : in Habenaria {H. albida, bifoHa, 

 viridis, Butterfly Orchis) the retinacula are distant : in Neotinea {N. intacta) 

 the pink perianth-segments are connivent : whilst in the preceding genera the 

 labellum is spurred, it is not spurred in Herminium {H. Monorchism the green 

 Musk Orchis). 



Fam. 3. Neottiince : pollinia usually soft and granular, either acrotonous or 

 altogether without caudicles. 



To the sub-family Cephalantherece, in which the labellum is transversely 

 segmented, belong the genera Cephalanthera, Epipactis, and Epipogium. 

 Cephalanthera (C grandifiora, C. ensifolia, C. rubra) and Epipactis [E. latifolia 

 and E. palustris), the Helleborines, are rhizomatous leafy plants with well- 

 developed leaves on the peduncles : the labellum is not spurred, and the rostel- 

 lum is rudimentary. Epipogium Gmelini is a saprophyte, has no roots, and 

 its leaves are scaly and not green ; it has granular pollinia with acrotonous 

 caudicles, a rostellum producing a retinaculum, and a spurred labellum ; the 

 flower is not resupinate. 



To the sub-family Spiranthece, characterised by a rostellum as long as the 

 anther, producing a retinaculum to which the granular pollinia (without cau- 



