THE ORCHIDS OF NEW ENGLAND. 123 
matter which envelopes the pollen-grains in Cypripedium and 
which can be drawn out into threads, we may suspect that in 
this latter genus—the least differentiated in structure of all 
the Orchidee—we see the primordial condition of the elastic 
threads by which the pollen-grains are tied together in other 
and more highly developed species. . . . In some Neottez, 
especially in Goodyera, we see the caudicle in a nascent con- 
dition projecting just beyond the pollen-mass, with the threads 
only partially coherent. . . . Inthe Ophrez we have bet- 
ter evidence than is offered by gradation, that their long, rigid 
and naked caudicles have been developed, at least partially, 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 cer- 
tain species; and on carefully opening several caudicles of 0. 
pyramidalts, 1 found in their centres fully half way down 
between the packets of pollen and the viscid disc,-‘many pollen- 
grains (consisting as usual, of four united grains), lying quite 
loose. These, from theirembedded position, could never by any 
possibility have been left on the stigma of a flower, and were 
absolutely useless.” He supposes that “the changes have not 
always been perfectly effected, and that during and after the 
many inherited stages of the abortion of the lower pollen- 
grains, and of the cohesion of the elastic threads, there still ex- 
isted a tendency to the production of a few grains where they 
were originally developed; and these were consequently left 
entangled within the now united threads of the caudicle. .. . 
The little clouds formed by the loose pollen-grains within the 
caudicles of O. pyramidalis are good evidence that an early pro- 
genitor of this plant had pollen-masses like those of Goodyera, 
and that the grains slowly disappeared from the lower parts, 
leaving the elastic threads naked and ready to cohere into a 
true caudicle.” 
