xiii LYCOPODINEJE S03 



vestigated by Bower (5) and Bertrand (3), and the former 

 regards it as the most primitive in structure of all the living 

 Pteridophytes. 



The sporophyte resembles in an extraordinary degree the 

 young sporophyte of Lycopodium, especially L. cernuum. It 

 grows from a small tubercle (protocorm), which is regarded as 

 homologous with the same structure in the embryo of Lyco- 

 podium. This protocorm in small plants produces only sterile 

 leaves — from four to twenty — and a small number of roots, 

 often only a single one. In more vigorous plants a smaller 

 number of sterile leaves is formed, but the apex of the proto- 

 corm grows into an elongated axis, bearing a single small stro- 

 bilus at the apex (Fig. 290, A). The structure of the latter 

 is essentially as in Lycopodium. The roots are produced exog- 

 enously, as in the Lycopodium embryo, and are in structure 

 much the same. All of the tissues are very simple, and none 

 of the organs show a single apical cell, except possibly the apex 

 of the strobilus, where such a single initial seems to be some- 

 times present (Fig. 290, B, i). At the end of the growing 

 season a new protocorm is formed. This arises directly from 

 the apex of the old one, where no strobilus is developed, but in 

 the latter case grows out upon a sort of peduncle from near the 

 base of one of the leaves. The development of the sporangia 

 is essentially the same as in L. selago (Fig. 290, B). 



The anatomy of the vegetative organs has been carefully 

 studied by Bertrand, and corresponds closely to that of Lyco- 

 podium, but the tissues are simpler. In the axis which bears 

 the strobilus there are about six xylem masses arranged in a 

 circle, but there is no definite endodermis limiting the central 

 cylinder. The root-bundle is diarch. 



Recently the gametophyte of Phylloglossum has been dis- 

 covered and described by Thomas (i). In its main features 

 it agrees with that of Lycopodium cernuum, having abundant 

 chlorophyll, and having much the same general structure. The 

 sexual organs and embryo also resemble those of L. cernuum. 



Bertrand states that M. L. Crie found that the spores ger- 

 minated readily, and produced a colourless prothallium like 

 that of the Ophioglossacese, both in form and in the structure 

 of the sexual organs, but that the spermatozoids are biciliate. 



These observations do not agree with the results of 

 Thomas's investigations. The latter observer thinks that per- 



