XIV LYCOPODINE/E 469 



About the time theit the stem apex becomes recognisable as 

 such, the first root appears as a surface outgrowth of the 

 protocorm, and strictly exogenous in origin. Not infrequently 

 the end of the primary root gives rise to a tubercle similar to 

 the protocorm. 



An interesting case was seen by Treub, where, apparently 

 by a longitudinal division of the young embryo, two embryos 

 were formed, much as is normally the case in some Gymno- 

 speriris. 



On comparing the two types of embryo found in L. 

 pJdegmaria and L. cermmin, the main differences are the almost 

 complete absence of the protocorm and greater development of 

 the suspensor in the former. L. inundatum^ as might be expected, 

 corresponds closely in the structure of the young sporophyte 

 with L. cernuum. 



Corresponding with the late appearance of the roots is the 

 late development of the vascular bundles, which, according to 

 Treub, are often quite absent from the cotyledon and even 

 occasionally from the second leaf. The protocorm of L. 

 cernuum and L. inundatum Treub regards as the remains of a 

 primitive structure originally possessed by the Pteridophytes, 

 which replaced the definite leafy axis found in the more 

 specialised existing forms. 



TJie Sporophyte 



In all species of Lycopodiinn the sporophyte possesses an 

 extensively branched stem, which may be upright, as in L. 

 cernuuni^ or extensively creeping, as in L. davatuni and other 

 species, where the main axis is a more or less completely 

 subterranean rhizome with upright secondary branches. In 

 the Tropics some species are epiphytes. The leaves are 

 always simple, and of small size. Each leaf has a single 

 median vascular bundle, which does not extend to the apex. 

 The arrangement of the leaves is usually spiral, and they are 

 uniformly distributed about the stem, and all alike ; but in a 

 few species, e.g. L. complanatuin, they are of two kinds and 

 arranged in four rows, as in most species of Selaginella. The 

 branching of the stem is either dichotomous or monopodial. 

 The roots, which are borne in acropetal succession (Bruchmann 

 found also in L. inundatum adventive roots), branch dichotom- 



