110 Transactions. 



rhizoid, and so comes into contact with the humus ; while in L. scariosum 

 the filaments of the fungus are found also in the cavities of the rhizoids. 



(6.) Reproductive Organs. — Antheridia in all three species were of the 

 usual Lycopodiaceous type, those in L. volubile projecting a little above 

 the surface, while those in L. scariosum and L. Billardieri were completely 

 sunk in the prothallium. 



The development of the archegonia is the same as in other species of 

 Lycopodium, the only point of variation being in the neck canal cells, which 

 number four to seven in L. volubile, six in L. scariosum, and five in L. 

 Billardieri. 



The paraphyses of L. Billardieri are composed of fewer cells than in 

 L. Selago and L. phlegmaria, and are usually unbranched. 



(7.) Young Sporophyte. — Though the embryology was not traced in 

 detail, the embryos of L. volubile and L. scariosum are undoubtedly of the 

 L. clavatum type. There is a large persistent foot and no sign of a proto- 

 corm. In L. Billardieri the foot is fairly large and persistent. 



General Remarks. 



In the gametophyte of Lycopodium there is much greater variation 

 than in any other vascular cyptogams. Thus, H. Bruchmann describes 

 five different types of prothallia — (1) L. clavatum, (2) L. complanatum, (3) L. 

 Selago, (4) L. inundatum, and (5) L. phlegmaria. After carefully examining 

 these different types he comes to the following conclusion : "It follows 

 from the above facts that the groups of Lycopodium characterized especiallv 

 by means of their sexual generation do not stand in close relation to one 

 another ; especially not such as one would expect in species of plants 

 which have found their position together in one genus. The knowledge 

 leads to a separation of the Lycopodiums into groups, or, still better, into 

 genera, to which it would be quite in place to give new names. There 

 arise as many groups as the sexual generation allows to be distinguished." 

 Thus, Bruchmann regards the species of Lycopodium as derived from several 

 stocks of Lycopodiaceous plants. This is essentially the same conclusion 

 as that arrived at by Dr. Treub in 1886, when, after remarking on the 

 great difference between the prothallia, embryos, and young plants of 

 L. cernuum and L. phlegmaria, he proceeds to say, " This is one of the 

 reasons why I believe I may offer the opinion that the profound differences 

 between the prothallia of the Lycopods are of very ancient date, and that 

 they are not the result of very recent adaptations." 



But another view of the variations in the prothallia of different species 

 of Lycopodium has been given by Lang in 1899, and by Goebel in his 

 '' Organography of Plants " in 1905, and it is this view that the facts 

 obtained in the present investigation seem to support. Lang's view is that 

 many of the differences between the different types of Lycopodium pro- 

 thallia are physiologically adaptive in character, and so are not of generic 

 value ; and similarly Goebel sees no valid ground for regarding the gap 

 between the several forms of the prothallia of the Lycopodia to be so great 

 as Treub and Bruchmann will have it. 



With regard to external form, the differences are not so great as they 

 appear, for L. Selago may be regarded as intermediate between the radial 

 green prothallia of L. cernuum and the filamentous saprophytic L. phleg- 

 maria. Again, in regard to internal structure Lang points out that the 

 differences are in the tissues infected by the fungus, and this has been seen 

 also to be the case in L. volubile and L. scariosum. Thus they are due to 



