LANDMARKS OF BOTANICAL HISTORY GREENE 237 



tion of seeing willows spring up as from that down, this neither 

 convinced him that all the other kinds of willow might be raised 

 in that way, nor even that any willow had ever borne a real seed. 

 He says that one out of the four species of willows which he de- 

 scribes can be propagated in this way; but he vouches for none of 

 the others; does not infer that the other three may be found pro- 

 ducible from "willow down." Nor did he have any idea that he 

 had planted willow seeds. 'The down takes the place of seed." 1 

 There are certain kinds of poplar, and even of maple, which he 

 thinks never bear seed at all, and which he therefore thinks came 

 into existence abiogenetically. These were dioecious trees, none 

 of them indigenous to Germany, and perhaps then existing there 

 in only the male sex. He has seen the tassels of Populus alba, 

 and knows them to be always deciduous ; also no one knows of any 

 seed as consequent to the flowering of Acer pseudo platanus. They 

 are seedless, and therefore, to the faith of Tragus, abiogenetic in 

 their origin. It even seems to be his opinion that certain plants 

 plentifully seed-bearing may upon occasion spring up and mature 

 in places where no seed of them had fallen. It is upon just this 

 theory that he accounts for the occurrence of individual plants of 

 many kinds on high walls of solid masonry and upon the roofs of 

 buildings. No orchids, in his understanding of them, produce seeds 

 at all. He is familiar with the fact that in autumn, as the plants 

 are withering away, a very fine dust falls from where the flowers 

 were, but he affirms that this perishes together with the season's 

 growth of stem and leaves. 2 He presents to his readers a strange 

 fancy about the primal origin and the perpetuation of this class of 

 plants. He is the first author to mention, and may or may not 

 have been first to observe in the flowers of orchids, resemblances to 

 birds and other flying things ; but he writes much as if he had been 

 the inventor of the theory that this kind of seedless plants originates 

 from certain excretions of birds. It is in the chapter that is devoted 

 to the birds' nest orchis that he explains this belief. Such plants, he 

 remarks, abound chiefly in and about thickets where small birds 

 mate and nest. 



The belief in all kinds of spontaneous generation, of even seed 

 plants as well as the seedless, did not preclude all research on 

 Tragus' part along these lines. There is a picturesque account of 

 nightly vigils in search of the problematic seeds of Osmunda regalis. 3 



1 Stirp. Comm., p. 1073. 



2 Ibid., p. 784. 



3 Ibid., p. 544. 



