138 MALAXED. Chap. V 



Tlie labelliim in all the species which I have seen, 

 more especially in B. rhizophorse, is remarkable by 

 being joined to the base of the column by a very 

 narrow, thin, white strap, which is highly elastic and 

 flexible ; it is even highly elastic when stretched, 

 like an india-rubber band. When the flowers of this 

 species were blown by a breath of wind the tongue-like 

 labella all oscillated to and fro in a very odd manner. 

 In some species not seen by me, as in B. harbigervm, 

 the labellum is furnished with a beard of fine hairs, 

 and these are said to cause the labellum to be in 

 almost constant motion from the slightest breath of 

 air. What the use can be of this extreme flexibility 

 and liability to movement in the labellum, I cannot 

 conjecture, unless it be to attract the notice of insects, 

 as the flowers of these species are dull-coloured, small, 

 and inconspicuous, instead of being large, brightly- 

 coloured, and conspicuous or odoriferous, as in so many 

 other Orchids. The labella of some of the species are 

 said to be irritable, but I could not detect a trace of 

 this quality in those examined by me. According to 

 Lindley, the labellum of the allied Megaclimum faha- 

 tum spontaneously oscillates up and down. 



The last genus of the Malaxeae which I will mention 

 is Dendrobium, of which one at least of the species, 

 namely D. chrysanthvm, is interesting, from being 

 apparently contrived to effect its own fertilisation, if 

 an insect, when visiting the flower, should fail to 

 remove the pollen-masses. The rostellum has an 

 upper and a small lower surface composed of mem- 

 brane; and between these is a thick mass of milky- 

 white matter which can be easily forced out. This 

 white matter is less viscid than is usual ; but when 

 exposed to the air a film forms over it in less than 

 half a minute, and it soon sets into a waxy or cheesy 



