1 6 



VASCULAR CRYPTOGAMS. 



tibro-vascular bundle of the mother-shoot runs into these papillae, without, however, 

 reaching more than half their height. The two small leaves of this fertile shoot, 

 which at one time were thought to be a bipartite leaf, originate separately on the 

 papillae, and unite only at a later period. The papilla itself consists, even at a 

 rather late period, of a homogeneous tissue which becomes separated, in a similar 

 manner to the anthers of Phanerogams, into parietal layers and three groups of 

 spore-mother-cells. Three loculi are thus formed, protruding strongly outwards 



"^ Fig. 310. — A transverse section of the.stem oi Selagi7iella denticiilata, the central vessels of the bundle not yet 



Hgnified ; B transverse section of the stem oi Lycopodiiivi Chamcecyparissus (X150). 



and separated by longitudinal walls and by an axial mass of tissue. These three 

 loculi I consider to be as many sporangia which are formed round the summit of 

 the fertile shoot, through which the axial fibro-vascular bundle ascends. 



The Systematic Classification of Lycopodiaceae can only be regarded as provisional until 

 the mode of germination of the remaining genera is accurately known. As we have seen, 

 they may in the meantime be arranged into two groups : — 



A. LycopodiecB ; with only one kind of spores. 



Lycopodium, Tmesipteris, Phylloglossum, Psilotum. 



B. Selaginelleas, with two kinds of spores. 



Selaginella, Isoetes. 



