156 



MANUAL OF BOTANY 



Fig. 914 



Phylloglossum has a tuberous stem, from the apex of which 

 about six leaves spring. These are longer than in Lycopodium 

 and form a sort of rosette, from the centre of which arises a pe- 

 duncle bearing the single flower. This is a small simple cone, the 

 upper leaves of which do not bear sporangia. The whole plant 

 is only a few inches in height. 



Psilotum is very much branched, and in appearance resembles 

 a very small bush. It has a much-branched subterranean 

 rhizome, from which arise numerous sub-aerial stems. There 

 are no roots, the subterranean shoots discharging their functions. 



The foliage leaves are 

 very much reduced, 

 being very small and 

 sparsely distributed. 

 The sporophylls are 

 bilobed and stalked. 



Tmesipteris grows 

 upon the trunks of tree 

 ferns, the stems being 

 pendulous and clus- 

 tered. Each stem is 

 slender and crowded 

 with linear sessile 

 foliage leaves, among 

 which occur sporo- 

 phylls much like the 

 former, but stalked and 

 bearing sporangia. 



The anatomy of 

 the stem in this group 

 presents some very 

 characteristic features. 

 The apical cell of the 

 lower Cryptogams becomes replaced by a small-celled meristem 

 resembling that of the apical growing point of the Phanerogams. 

 In a few cases, but only exceptionally, an apical cell occurs. The 

 stem is monostelic, and its vascular bundles are arranged radially 

 as in most roots {fig. 915). There are generally a number of wood 

 and of bast bundles, the protoxylem and protophloem of which 

 are placed alternately in a circle round the stele, abutting on the 

 pseudo-pericycle. As the wood develops the separate bundles 

 become united together, fusing into masses of irregular pattern, 

 between which lie masses of bast similarly formed by fusion of the 



Fig. 914. Lycopodium inundatum. Marsh Club-moss- 

 The stem is creeping, and bears umnerous small 

 sessile imbricate leaves. 



