176 Transactions. 



Treub (30) has described the prothalli of the four following tropical 

 epiphytic species: L. Phlegmaria Linn., L. carinatum Desv., L. nummulari- 

 folium Blume, and L. Hippuris Desv. Of these four species. L. Phlegmaria 

 and L. mimmtdarifolium belong, according to Pritzel's classification, to the 

 Phlegmaria section, L. Hippuris to the Euselago subsection, and L. carinatum 

 to the Siibselago subsection of the Selago section. They thus cover between 

 them all the main divisions of the subgenus Urostachya. According to 

 Treub's conclusions, the prothalli of all these four species are alike, belonging 

 to that form of the Lycopodium prothallus known as the Phlegmaria type. 

 That of L. carinatum is exactly like that of L. Phlegmaria. The prothallus 

 of L. Hippuris, however, is much larger and thicker, and that of L. nummu- 

 lar if olium very much thinner and more delicate, than that of the type 

 species. 



Miss Edgerley (12, pp. 104-9) has described the prothallus of the New 

 Zealand species L. Billardieri, and her results are in close accord with my 

 own. It corresponds very closely with that of L. Phlegmaria both as 

 regards external form and internal structure. There are, however, two 

 characteristic differences to be noted. In the case of L. Phlegmaria the 

 paraphysis is composed of a linear row of as many as a dozen cells, and 

 it may also branch, whereas in L. Billardieri it is much simpler in form, is 

 always unbranched, and is generally only three cells in length. Also, 

 although I have examined a very large number of prothalli of the three 

 New Zealand species mentioned above, I have never observed any vegetative 

 buds of either of the kinds described by Treub as occurring freely in the 

 prothallus of L. Phlegmaria. But in the New Zealand species short club- 

 shaped richly-stored resting vegetative processes commonly occur. 



The prothallus of L. Selago has been described by Bruchmann (5), 

 and presents some exceedingly interesting modifications of form. Bruch- 

 mann says (5, p. 85), " This variety of form of the prothalli seems to be 

 dependent mostly on the soil in which they are produced. The elongated 

 cylindrical forms are found especially in firm soil, in which they strove 

 towards its surface mostly in a vertical direction. In loose soil, especially 

 near the surface, I came across more thickset and flat forms of pro- 

 thalli." Moreover, besides the subterranean forms of prothallus of this 

 species, he found some which grew wholly or partly at the surface of the 

 earth, and which in their upper part showed a thoroughly green colouring. 

 Such prothalli lived as semi-saprophytes, and by their manner of life formed, 

 as Bruchmann himself says, " an interesting transition between the assimi- 

 lating and the merely saprophytic forms " of the Lycopodium prothallus. 

 Every complete prothallus, whether of the elongated or thickset form, 

 shows at the original end a tiny, usually bent point, which is the region 

 immediately developed from the spore, and which develops above into the 

 cone-shaped tissue-body. The prothallus is abundantly supplied with long 

 rhizoids ; and many-celled paraphyses, similar to those described by Treub 

 in L. Phlegmaria, are present, along with the sexual organs. Spessard (25) 

 has recently given a short account of the prothallus of L. lucidulum as it 

 occurs in America. It is a cylindrical elongated body, bearing paraphyses 

 at its uppermost end. 



In discussing the different types of Lycopodium. prothallus Lang 

 (24, pp. 305-6) says with regard to that of L. Selago, " The two forms of 

 prothallus found in L. Selago give the clue to the more specialized sapro- 

 phytic types, which in the deeper-growing subterranean species retain the 

 radial symmetry while becoming modified in shape. On the other hand, the 



