i 9 i 7 ] CHAMBERLAIN— LYCOPODIUM 53 



together with the results of DeBary, who had described early 

 stages of L. inundatum from cultures, made it possible to make a 

 general outline of the development from the germination of the 

 spore up to the adult prothallium with sporelings attached. 



Beck sowed the spores of various species under various condi- 

 tions, but L. inundatum was the only one to germinate and the pro- 

 thallia did not get beyond the io-cell stage. He asserted that 

 after 2 years the spores of L. clavatum showed chlorophyll and 

 looked as if they were about to germinate, but no cell division 

 occurred. 



Since Fankhouser's paper appeared, 3 men have made large 

 contributions to our knowledge of these peculiar prothallia. In 



1884, 1886, 1888, and 1889, Treub (7, 9, n, 12) published a splendid 

 series of researches upon the prothallia of Javanese species. In 



1885, Bruchmann (8) began his patient and persistent researches 

 upon the difficult temperate species with subterranean prothallia 

 which had baffled all previous investigators; and in 1887, Goebel 

 (10) found prothallia of L. inundatum, so that, with the stages 

 secured by DeBary, he was able to give a connected account of 

 this species. 



Treub began his series with an investigation of L. cernuum. 

 He germinated the spores of this familiar tropical species and some 

 of the prothallia reached the early antheridium stage before they 

 died. However, he found abundant material growing wild, and 

 so had a complete series from the germination of the spore to the 

 adult prothallium with embryos and older sporelings. 



The prothallia are green and grow on the surface of the sub- 

 stratum, the largest reaching a height of 2 mm. When the spore 

 germinates, a more or less spherical body is formed, about 8 or 10 

 cells in diameter. From the top of this body, which Treub called 

 the "primary tubercle," an alga-like filament then develops, at 

 first consisting of a single row of cells, but soon dividing in all 

 planes, so that a stout cylindrical body is formed more than twice 

 the diameter of the primary tubercle and 5 or 6 times as long. The 

 tip of the cylindrical portion is profusely branched, and at the base 

 of the branches the antheridia and archegonia are borne. The 

 embryogeny is particularly interesting, since the fertilized egg does 



