ZING1BERACE.E OR SC1TAMINE.E. 517 



often sheathing leaves, and generally showy, attractive flowers. Some- 

 times buds are produced on the margins of the leaves (fig. 214). They 

 are natives of almost all parts of the world, but they abound in moist 

 tropical regions. They are not found in the arctic regions, nor in very 

 dry climates. Some are terrestrial, and others are epiphytic. The 

 former are commonly seen in temperate climates, the latter in warm 

 regions. Disa grandiflora is found on Table Mountain at an elevation 

 of 3,582 feet. The only known locality for it is in a marshy hollow 

 near the eastern extremity of the summit, where it is abundant among 

 rushes on the margins of small pools and streamlets in a black boggy 

 soil. Two rare species of Disa are also seen there, D. ferruginea and 

 tenuifolia. Oncidium nubigenum is found on the Andes, near Quito, at 

 an elevation of 14,000 feet above the level of the sea. Epidendrum 

 frigidum occurs in Columbia at an elevation of 12,000 to 13,000 feet 

 (mean temperature 46), and is covered with a sort of varnish. Lind- 

 ley, who is our best authority on Orchids, has divided them into 

 various tribes. He enumerates 396 genera, including about 3000 

 species; of these, 16 genera and 40 species are British. 



1057. The plants of this order are well distinguished by the pecu- 

 liar forms of their flowers, their remarkable lip, gynandrous stamens, 

 and pollen-masses. Their flowers often resemble insects, as butter- 

 flies, moths, bees, flies, and spiders ; or birds, as doves and eagles ; 

 or reptiles, as snakes, lizards, and frogs. The colours and spots on 

 the perianth sometimes give the appearance of the skins of quadrupeds, 

 as the leopard and tiger. These resemblances are often indicated in 

 the generic and specific names. The labellum, in some instances, dis- 

 plays peculiar irritability (^[ 665). 



1058. Mucilaginous properties occur in many of the plants of this 

 order. Some are aromatic and fragrant; others are antispasmodic 

 and tonic. The tuberous roots of some yield a nutritious substance 

 called Salep, which consists chiefly of bassorin, some soluble gum, and a 

 little starch. The orchid yielding it is not well known ; some say 

 that it is Orchis mascula, others 0. papilionacea, Mono and militaris, 

 others Eulophia vera and campestris. Salep forms an article of diet 

 fitted for convalescents, when boiled with water or milk. The roots 

 of Aplectrum hyemale contain a very glutinous matter, and hence the 

 plant is called in America Putty-wort. The fleshy pod-like fruit of 

 Vanilla planifolia, claviculata, and other species, constitutes the sub- 

 stance called Vanilla, which is used in confectionery, and in flavour- 

 ing chocolate. It contains an oil and much benzoic acid. A blue 

 colouring matter has been found in some of the orchids. The 

 odour of many of them is very fragrant ; sometimes it is oppressive ; 

 at other tunes, as in Malachadenia clavata, it is very fetid, resembling 

 carrion. 



1059. Order 186. Zingiberacete, or Scltaminefe, the Ginger 



