258 GRADATION OF ORGANS. Chap. IX. 



single grains are embedded in a glutinous fluid ; in 

 all the other Orchids seen by me (except the degraded 

 Cephalanthera) the grains are united three or four 

 together.* These compound grains are tied one to 

 the other by elastic threads, but they often form 

 packets which are tied together in like manner, or 

 they are cemented into the so-called waxy masses. 

 The waxy masses graduate in the Epidendrese and 

 Yandese from eight to four, to two, and, by the co- 

 hesion of the two, into a single mass. In some of the 

 Epidendrese we have both kinds of pollen within the 

 same anther, namely, large waxy masses, and caudicles 

 formed of elastic threads with numerous compound 

 grains adhering to them. 



I can throw no light on the nature of the cohesion 

 of the pollen in the waxy masses ; when they are 

 placed in water for three or four days, the compound 

 grains readily fall apart ; but the four grains of which 

 each is formed still firmly cohere ; so that the nature 

 of the cohesion in the two cases must be different. 

 The elastic threads by which the packets of pollen are 



* In several cases I have ob- tubes are, ot least at first, formed 



served four tubes emitted from exclusively at the expense of the 



the four grains which fonn one of contents of the poUen-graina, 



the compound grains. In some Havingalludedtothemonstrous 



semi-monstrous flowers of Malaxis flowers of the Aceras, I will add 



paludosa, and of Aceras anthropo- that I examined several (always 



plwra, and in perfect flowers of the lowest on the spike) in which 



Neottia nidus-avis, I have observed the labellum was hardly developed, 



tubes emitted from the pollen- and was pressed close agninst the 



grains, whilst still within the stigmsi. The rostellum was not 



anther and not in contact with developed, so that the polUnia did 



the stigma. I have thought this not possess viscid discs ; but the 



worth mentioning as K. Brown moat cm'ious feature was, that the 



(' Linn. Transact.' vol. xvi. p. 729) two anther-cells had become, appa- 



states, apparently with some sur- rently in consequence of the posi- 



prise, that the pollen-tubes were tion of the rudimentary labellum, 



eiTiitted from the pollen, whilst widely separated, and were joined 



still within the anther, in a decay- by a connective membrane, almost 



ing flower of Asolepias. These as broad as tha,t of Babenaria 



cases show that the protruding clilorantha ! 



