Ohap. V. OATTLEYA. 143 



two great tribes might have been run together ; as the 

 distinction drawn from the presence of caudicles does 

 not always hold good. But diiBculties of this nature 

 are frequently encountered in the classification of 

 largely developed or so-called natural groups, in which 

 there has been comparatively little extinction. 



I will begin with the genus Cattleya, of which I 

 have examined several species. These are fertilised 

 in a very simple manner, different from that in any 

 British Orchid. The rostellum {r, fig. 22, A, B) is a 

 broad, tongue-shaped projection, which arches slightly 

 over the stigma ; the upper surface is formed of smooth 

 membrane ; the lower surface together with the central 

 portion (originally a mass of cells) consists of a very 

 thick layer of viscid matter. This viscid mass is 

 hardly separated from the viscid matter thickly coating 

 the stigmatic surface which lies close beneath the ros- 

 tellum. The projecting upper lip of the anther rests 

 on, and opens close over the base of the upper mem- 

 branous surface of the tongue-shaped rostellum. The 

 anther is kept closed by a spring, at its point of at- 

 tachment on the top of the column. The pollinia 

 consist of four (or eight in Cattleya crispa) waxy 

 masses, each furnished (see figs. C and D) with a 

 ribbon-like tail, formed of a bundle of highly elastic 

 threads, to which numerous separate pollen-grains are 

 attached. The pollen therefore consists of two kinds, 

 namely, waxy masses and separate though compound 

 grains (each, as usual, consisting of four) united by 

 elastic threads. This latter kind of pollen is identical 

 with that of Epipactis and other Neottese.* These tails, 

 with their appended pollen-grains, act as caudicles, 



* The pollen-masses of Bli tia published by Lindley in his ' II- 

 are admirably represented ou a lustrations.' 

 larse scale in Bauer's drawings, 



