MASDEVALTJA. 15 



Curious as are these peculiarities in structure, it is certain that they 

 have an important bearing on the economy of the plants with an 

 especial aim to the fertilisation of the flowers by insect agency, since 

 it is impossible to see by Avhat other means this is effected. The 

 gorgeous colours of the sepals of some species, and the powerful 

 odour (almost foetor) of the labellum of others have doubtless been given 

 them to attract insects to the flower ; these would naturally alight 

 either on the broad lateral sepals, or, where that organ is large enough, 

 on the labellum, which is usually fluted or channelled, or, as in the 

 saccolabiate group, curiously sculptured, but in such a way as to 

 ' afford a guide to an insect to the bottom of the sepaline tube where 

 honey would be most likely to be secreted, although we have never 

 detected any such secretion in any of the species cultivated by us. 

 It is difficult to see how an insect that has once made its way to 

 the foot of the column, via the labellum, can withdraw without 

 carrying away the very small and very light pollinia, and which drop 

 from the anther chamber (clinandrum) upon the slightest touch ; 

 moreover the labellum itself is, in the majority of the species, parallel 

 with the column and almost adpressed to it except at the reflexed 

 tip, so that an insect could scarcely make its escape that way without 

 either touching the rostellum or some other part of the sexual apparatus. 

 In the same way, an insect loaded with one or more of the pollinia, 

 on entermg a second flower would scarcely fail to deposit them on 

 the stigmatic surface, where they would be retained by the viscid 

 secretion. No instance of a Masdevallia being self-fertilising has yet 

 been observed by us, but at least two undoubted natural hybrids {see 

 mfra) have been introduced with one or other of the recognised 

 parents ; it is not possible to imagine that the cross could have been 

 effected otherwise than by uisect agency. 

 The essential characters of Masdevallia are : — 



The sepals are connate at the base, usually into a sub-cylindric or 

 broadly campanulate tube, the free portions, with very few exceptions, 

 being produced into long, slender tails. 



The petals are small, parallel with the column, and generally narrow. 



The Up is also small, polymorphous, and articulated at the base of 

 the column. 



The column is either margined or v/inged, and is sometimes produced 

 at the base into a short foot ; the pollinia are two, without caudicle. 



The cajisule is cylindric or fusiform, six-ribbed, from one-half of an 

 inch to an inch long.* 



In their vegetation the Masdevallias are caespitose or tufted herbs 

 without pseudo-bulbs. — 



* In Masdevallia Chimayra and other saccolabiate species, the capsule is ovoid-orbicular, 

 about as large as a medium-sized gooseberry, with three pairs of prominent ribs, more or 

 less serrate at the edge. 



