52 GENERAL REVIEW OF THE OKCHIDE.%:. 



the upper face and a corresponding keel, mure (jr less defined on the ' 

 under one, l)ut sometimes the leaves are conduplicate, folded from 



the base to the apex. In a few species the leaves are of the " centric " ; 



type, much resemhlin^ti,' the stem from ■which they spring, being terete, | 

 dull in colour and usually sharp pointed as in Vanda teres, Aerides 



Vandarmn, Anqnecum Scottiaimm, the genus Luisia, throughout, many ' 



species of Sarcanthus, etc. The leaves of monopodial orchids are nearly i 

 always leathery in texture and persistent several years under cultivation; 

 deciduous species occur in Phalrenopsis [P. Lowii), Sarcochilus {S. luniferm) 

 and one or two others. 



The inflorescence is racemose, or less frequently some modification of ! 



the raceme, chiefly the panicle. In Rhynchostylis and in many species ; 



of Aerides, Saccolabium, Sarcochilus the raceme is very dense and , 



man}'-fluwered. In Arachnanthe, A^'anda, Stauropsis, etc., it is often i 



short, lax and few-flowered. In Arachnantlie Lowii the floral axes ; 

 extend several feet in length and bear in the aggregate several hundreds 



of flowers ; in some species of Angraecum {e.g., A. pertusum, A. ■ 



citratum) the flowers are secund, all facing one way, and their perianth j 



segments Ix'ing nearly in the same plane, the inflorescence has a J 



strikingly formal appearance. The finest instances of the panicidate ■ 



inflorescence are sometimes seen in Piadd'aupsis Schilleritma, P. ; 

 Stuart ia?ia, Aerides crisp/uu, and A. multifioruia. 



The sympodial orchids constitute by far the largest division ; all 

 the terrestrial kinds both tropical and temperate, all the pseudo- ! 

 bulbous species, and all whose stems are matured in one season j 

 are included in it. In these orchids new growth generally begins J 

 with the development of leaf-like scales which gradually pass into j 

 true leaves, so that it sometimes happens that between the first 

 pair of leaf scales and the true leaves many intermediate forms 

 occur. In pseudo-bulbous species with few leaves, the pseudo-bulbs 

 are often formed between the first pair of true leaves, and one or 

 two more leaves are produced from the apex of the pseudo-bulb, 

 as in Odontoglossum, Oncidium, Miltonia, etc. In other species the 

 vegetative axes are often prolonged into leafy stems of varying 

 length and thickness. In both cases the old pseudo- bulbs and the , 

 old stems persist for some time after they have become effete, the 

 terminal ones alone being floriferous.* ; 



The group of sympodial orchids with lateral inflorescence is a very i 



* The stems of some of the evergreen Dendrobes iu the sub-section Calostachy^ [Dcn- 

 drobium Farmeri, D. deiisijlorum, etc.) are an exception ; these produce their handsome 

 thyrsoid racemes three or four years iu succession. 



