776 VL OEOHIDBJl. 



of an outer whorl of three stamens represented by one normal anther and two rudimentary ones opposite 

 to the sepals; sometimes of an inner whorl, equally triandroua, of which one stamen is arrested, and two 

 are normal, opposite to each lateral petal, and alternating with the carpels. This ternary arrangement is 

 confirmed by Apostasice, which are closely allied to Orchidets in their petaloid hexaphyllous 2-seriate 

 irregular perianth, gynandrous androecium composed of three stamens one of which is often arrested, 

 and which are only distinguished by their granular pollen and their 3-celled ovary. Orchideca also 

 approach Burmanniaceee in epigyny, l-ceUed ovary, S-valved capsule, and scobiform seeds ; and Cannem 

 in the inferior ovaiy, the perianth, and the androecium reduced to a single stamen. 



The floral structure of Orchidem sometimes presents a singularity equally remarkable and rare in 

 the Vegetable Kingdom: we find on the same inflorescence dimorphous flowers {Cychnoehes ventri- 

 eo^nf, Vanda Loioii, Spievlcea, Dralc<sa, &c) ; or even three different forms {Catasettim, Myantkus, 

 Cyelinothei).' 



In Orchidem, owing to the consistenee of their pollen, extraneous agency is required to ensure ferti- 

 lization, which, as in Asclepiadees, is effected by insects ; and in our hothouses, where these auxiliaries 

 are wanting, fertilization must be artificially secured. . In some species the lip is irritable ; it oscillates 

 opposite the column (Megacliniian), or turns round it (Caleana); on an insect settling on the surface 

 of the lip, the latter quickly approaches the column, and presses the insect against it, which in its 

 efibrts to disengage itself breaks up and crushes the pollen- masses, and spreads them over the stigma.' 



Orchidecs mostly inhabit tropical forests ; they abound especially in the New World, where their 

 numerous species generally grow on the trunks of trees, to which they attach themselves by their long 

 adventitious roots ; but they are terrestrial in the temperate regions of the northern hemisphere ; they 

 become rare near the pole, and Calypso horealis is the only one which reaches 68° north latitude. 

 Malaxidem inhabit the Indian continent and islands, and principally the Malay Archipelago ; they are 

 less numerous in tropical America and the islands of South Africa ; they are rather frequent in Australia 

 and the Pacific Islands, but rare in the northern hemisphere, and entirely absent from the MediteiTanean 

 region, temperate America, and the Oape of Good Hope. [lAparis, Malaxis, and Calypso are all European ; 

 iiparis, Microstylis, and Calypso are temperate American; Liparis and Polystachya are both South 

 African.] Epidendrets nearly all belong to the tropical regions of the New World ; some, however, 

 inhabit the same zone in Asia ; a very few [many species of- Ccelogyne] are found in North India and near 

 China ; one species only advances as far as South Carolina. Vandeee are found in equal numbers in 

 tropical Asia and America ; they are common in Madagascar, rare in Africa, and very rare beyond the 

 tropics. OphrydecB inhabit all temperate and sub-tropical regions, especially Central and Mediter- 

 ranean Europe, and South Africp. ; they are rarer in the tropics. Necfttiece principally grow in temperate 

 Asia and Australia ; they are much less numerous within the tropic of Cancer, and very rare in Africa. 

 Arethvsece abound in south temperate regions, and especially Australia [and South Africa] ; they become 

 rarer in the tropics and north temperate zone. Ohlorcece extend as far south as the Straits of Magellan. 

 CypripediecB inhabit the tempei'ate and cool regions of tha northern hemisphere ; they are somewhat 

 frequent in America ; [and are spread over tropical Asia and its islands]. 



Orchidem are much admired for the singularity, beauty and scent of their flowers. Their cultivation, 

 which usually requires a hothouse and extreme care, has during the last forty years become an absolute 

 passion in Europe. Linnaeus, in the middle of the last century, knew but a dozen exotic Orchids, whereas 

 at the present day about 2,500 are known to English horticulturists. 



Of the few Orchids which are of use to man, the Vanillas {Vanilla olaviciilata, planifalia, &c.) hold 

 the first rank. They are sarmentose plants, natives of the hot and damp regions of Mexico, Colombia, 

 and Guiana [and tropical Africa]. Their fruit is a fleshy long capsule, and the black globose seeds 

 are enveloped in a special tissue which secretes a balsamic oil ; if kept in a dry place the capsule becomes 

 covered with pointed and brilliant crystals of benzoic acid, and imparts its delicious perfume to various 

 delicate dishes, chocolates, liqueurs, &c. The Faham {Angrcecumfragrana) is a native of Bourbon; its 

 leaves, known as Bourbon Tea, taste of bitter almonds and smell like Tonquin beans ; they are used to 

 stimulate digestion, and in pulmonary consumption. Salep, which is imported from Asia Minor and 

 Persia, is produced by the tubers of several species of Orchis, which are equally natives of Europe 



' Poi an account of the phenomena of Orchid fertilization, see Darwin ' On the Fertilization of Orchids.'— I;d. 



