4H GENERAL REVIEW. 



THE ORCHID FAMILY (Orchidatea)* 



We have here a large natural group, comprising some four 

 or five thousand perennial evergreen or herbaceous plants, 

 distributed over nearly every part of both hemispheres. For 

 practical purposes, they are divided into terrestrial kinds, which 

 are for the most part deciduous or herbaceous tuberous-rooted 

 species, found in temperate regions ; and epiphytal species, or 

 such as grow upon trees, sending both roots and growth into 

 the air, as in Denbrobium, Angr&cum, some Odontoglots, as O. 

 Alexandra, O. Pescatorei, &c., Cypripediums, as C. Lowii, 

 Aerides or " air-plants," Vanda, Renanthem, and many others, 

 nearly all natives of hot, moist regions in Asia and South 

 America a few coming from moist parts of tropical Africa. 

 Many Orchids, and more especially species of Vanda, Aerides, 

 Phal&nopsis, Angrtzcum, Cattleya, Oncidium, and Saccolabium, 

 are noted as being amongst the most rare and beautiful of 

 all tropical flowers ; and of late years they, and others, have 

 occupied prominent positions in our gardens here at home. 

 Many species have thickened stems or pseudo -bulbs, these 

 being formed by the cohesion of the thickened leaf-stalks or 

 petioles, and their use is to serve as reservoirs of nutriment, so 

 as to enable the plant to withstand the hot and dry or rainless 

 period of the year in its native habitat ; and this thickening of 

 the growth is somewhat analogous to the succulence of Cacti, 

 different species of Euphorbia, Sedum, Semperuivum, Eche- 

 veria, and other plants, and it enables them to resist periods 

 of unsuitable climatic conditions, and at the same time retain 

 their permanent or evergreen character. In their native habi- 

 tats, Orchids are naturally multiplied by seeds; and the fertil- 

 isation of a very large proportion of them is dependent on 

 insect agency. This also accounts for the extreme variability 

 of some species of Phalanopsis, Odonloglossum, and Cattleya 

 different forms, and probably different species, becoming fer- 

 tilised with the pollen of other species or varieties. Thus, 

 Phal&nopsis Veitchiana is supposed to be a natural mule be- 

 tween P. (equestris] rosea and P. Schilleriana. In alluding to 

 supposed natural hybrids in the 'Gardener's Chronicle' (March 

 6) 1875, P- 3 OI ' 2 > Prof- Reichenbach remarks that Phalanopsis 



* The reader interested in the cross-fertilisation of Orchids should see 

 Darwin's work, ' On the various contrivances by which British and Foreign 

 Orchids are Fertilised by Insects, and on the good effects of Intercrossing' 

 (Murray) ; also, ' Experiments on the Fertilisation of Orchids in the Royal 

 Botanic Garden of Edinburgh' (Scott). 



