IG GENERAL REVIEW OF THE ORCHIDEA'. 



The sepals or outermost series of iieiiaiilli seLijiiieiits are generally 

 uiiiforin, lull imiiierdus (leviatimis from tlie eiiuality ami similarity of 

 the three nceiii'. The most usual deviatinu is seen in the upper or 

 dorsal se[>al, which is often of a dillerent size anil shai)e from the 

 lateral iwo as in Renanthera (tyite spe(ues), Restrepia, Cirrhopetalum, and 

 many Oiieiils. In Masdevallia the three sepals are uniteil at their 

 hases into a lulie and prolonj^cd into slender tails at the free end. 

 In Rodriguezia the two lateral sepals form a hoat-like hody of very 

 curious structure. In CryptnpJKiranthus the two lateral sepals an; not 

 only joined together hut they cohere In the upiii'i' one hoth at the 

 hase and ai)ex, s(t that tin; llower never opens, and in Comi»arettia 

 they are produced at lln'ir hase int(j a long sjair. In Oariilinin Papilio 

 and the closely allied On. Kraineriaiiinii the two lateral sepals are not 

 only of very different shape from the ujjper one Init they o,re more 

 hrightly coloured than the petals, an unusual occurreiu:e in Oncidium. 

 In Cypripedium the two lateral se})als are always joined together into a 

 single Itlade which, in the Indo-Malayan species, is usually smaller than 

 the ui)per one. Other deviations are describeil under the several 

 genera in which they occur. 



The eipiality of the two petals is constant, l)ut great diversity occurs 

 in the part they take in the general aspect of the ilower, of which, 

 comhined with the lahellum, they are often the most conspicuous 

 ornament. But in Masdevallia, Cryptophoranthus, Cirrhopetalum and 

 other genera they are reduced to small insignificant bodies that in 

 Masdevallia are often quite concealed within the sepaline tube, while 

 in Cypripedium Sanilerianiun, C. caiulatuni, C. carict'nnm and others 

 they are enormously elongated into rihhondike tails many inches in 

 length. In the Filifene sub-section of Ccslogyne the narrow linear 

 l)etals are (juite a subordinate feature of the flower, but in many of 

 the Cyrtochiloid ()ncids they arc the most conspicuous i)arts and much 

 larger than the lahellum. The fringed petals of Dei/drobium Harccij- 

 aiiwii are a remarkable exception in that genus, in which these organs 

 are always entire. 



The lahellum is by far the most important of the perianth segment's 

 and it is also the most ])olymorphous ; but into whatever form it has 

 been moulded (and so far as our observations have extended, in no 

 two genera is it exactly alike and it varies also considerably in every 

 largo genus), its structure is always such as to secure tin; greatest 

 elliciency in the part it performs as an aid to the fertilisation of the 

 llower. Throughout the Synopses of the Genera and Species, a large 

 number of illustrations of this wonderful organ is given, so that only 

 some typical forms need here be noted. The lahellum is usually 

 attached to the column by a short claw or 7mr/ui,s which is sometimes 

 so delicately hinged on it that the blade vibrates on the slightest 

 force being im})arted to it, for instance, by a breath of air. A 



