BY T. WHITELEGGE. 559 



capped by a series of cells resembling- greatly tlie cells on the 

 dome; the narrow end consisted of a continuous cell-sbructure 

 much like that of a prothallus, but smaller than any I have ever 

 seen. There were other cellular structures present bearing the 

 same kind of cells, but these having been l)roken in the mount- 

 ing, the cells were visible only on the inside. These bodies 

 appear to have been round. The outer surface presents a 

 series of projecting cells, many of wliich bear rhizoids. The 

 material from which the sUde was made was procured from the 

 interior of a single synangium. 



After the rough draft of this jtapei' liafl bee'n prepared, the 

 Rev. W. W. AVatts called my attention to a note in Spring's 

 "Lj'copodiaceie" (1842 and 1849), which is of great interest in 

 the light of the researches recorded in the present paper. The 

 following is jNIr. Watts" translation of Spring's observation, under 

 Psilotum, on p. 268 of his work: "If tlie spores are thrown into 

 water, they execute very rapid movements (mouvements de tre- 

 pidation) and speedily envelop themselves in a kind of cloud. 

 According t(j [Sir] Robert BiT)wn's observations (Prodr., p. 164), 

 this cloud is due to a fine powder, which escapes from the spores. 

 Kaulfuss has observed, upon the middle of the internal margin 

 of the spores, a black point, which was in touch (en rapport) 

 with a little vesicule, and which vanished, at the same time as 

 this last, in the water. Although I have not had the good 

 fortune to see that kind of 'aile seminal,' I recall this fact to 

 induce botanists, who have living plants of Psilotum at their 

 disposal, to direct their investigations to this point." Robert 

 Brown's description of the species of Psilotum, although brief, 

 gives an accurate account of what happens when antheridia 

 bearing spores are placed in water. The observation recorded 

 by Kaulfuss may possibly refer to the deeply stained female 

 gametophyte, which is just as easily detached from the spore as 

 the male. 



After having studied Fxllofum, I turned to the closely allied 

 Tnipxipteris. A>s I could not find spores in just the right stage 

 for sowing, it struck me as possible that suitably developed 



