260 GKADATION OF ORGANS. Chap. IX. 



The caudicle, when largely developed and destitute 

 of pollen-grains, is the most striking of the many pecu- 

 liarities presented by the pollinia. In some Keottea?, 

 especially in Goody era, ^ve see it in a nascent con- 

 dition, projecting just beyond the jjollen-mass, with 

 the threads only partially coherent. In the Yandete 

 by tracing the gradation from the ordinary naked 

 condition of the caudicle, through Ly caste in \\bich 

 it is almost naked, through Calanthe, to Cymbidhim 

 giganteum, in which it is covered with pollen-grains, it 

 seems probable that its ordinary condition has been 

 arrived at by the modification of a pollinium like 

 that of one of the Epldendrea; ; namely, by the abor- 

 tion of the pollen-grains which primordially adhered to 

 separate elastic threads, and afterwards by the cohesion 

 of these threads. 



In the Ophreae we have better evidence than is 

 aftbrded by gradation, that their long, rigid and 

 naked caudicles have been developed, at least partiallv, 

 by the abortion of the greater number of the lower 

 pollen-grains and by the cohesion of the elastic threads 

 by which these grains were tied together. I had often 

 observed a cloudy appearance in the middle of the 

 translucent caudicles in certain species ; and on care- 

 fully opening several caudicles of Orchis pyramidalis, 

 I found in their centres, fully half-way down between 

 the packets of pollen and the \ iscid disc, many pollen- 

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



flora has no rost.ellum to secrete and stigma ; yet I found in one 



the above thick fluid, yet the cf these auricles a distinct caudicle 



jwllcn-iiiains are thus united. In which necessarily had no disc at 



a nion^tmus specimen of Orchis its extremity), and this caudicle 



■jiyramidah'x the auricles, or rudi- could not possibly liave been 



mcntary aiitliirs on each side of secreted by the rostellum f>r 



the ]Moper anther, luid become stigma. T could advance addi- 



]iartly devebiiied, and they stood tiomd evidence, but it WOuM be 



quite oi. one side of the rostellum superfluous. 



