THE MOXOCOTYLEDONES 



2109 



Fig. 2048. — Xeottia uidus-aiis. A, Column. Compare with Listera, Fig. 2043. B, Flower, 

 face view showing the nectar trough in the labellum. C, Flower in profile. (A and C 

 after Fitch.) 



pollination may readily take place by the very crumbling pollen falling 

 automatically upon the stigma. 



2. Kerosphaereae. The poUinia are hard and waxy or bony in con- 

 sistency and the anthers are generally deciduous. The in- 

 florescence may be either terminal or lateral. 



This is a very large tribe and has been further subdivided into a series of 

 sections : 



(i) Acranthae. Inflorescence usually terminal or, by abortion of 

 the terminal inflorescence, may be axillary in the upper- 

 most leaves. Coelogyne, Dendrobium, Liparis, Ham- 

 }?7orbva, Corallorhiza, Epidendriim, Cattleya. 

 (ii) Pleuranthae. Inflorescence usually lateral, arising near the 

 base of the pseudo-bulb or in the axils of the lower leaves 

 or sheaths. 



[a] Sympodiales: Plants forming a sympodium in which the 

 stem ends in leaves. BiilbophyUum, Cynibidiuin, Onci- 

 diiim, Maxillaria, Odontoglossum, Calantfie, Phajiis. 



(b) Monopodiales: Plants forming a monopodium, stem 

 with indefinite apical growth. Vanda, Angraecii/n, 

 Polyrrhiza, Catasetum. 



The great majority of these genera are tropical in distribution and many 

 are epiphvtes in the tropical rain forests. Only three species are found in 

 Britain, e.g., Liparis /of .?//>' (Two-leaved Liparis), Hammarbya pahidosa (Bog 

 Orchid) and Corallorhiza trifida (Spurless Coral Root). None of them is 

 common. The genera belonging to this tribe, however, produce some of the 

 most spectacular flowers, both in respect to shape and colour as well as in 

 size. They therefore form the basis of most of the hybrid orchids which 



