34 LYCOPODIALES [CH. XIV 



small scale-like sporophylls, each subtending a single sporan- 

 gium ^- 



Lycopodiuin. It would be out of place in a volume devoted 

 mainly to fossil plants to attempt a comprehensive account of 

 the general morphology of recent species, and indeed our 

 knowledge of the anatomical characters of the genus is still 

 somewhat meagre. For purposes of comparison with extinct 

 types, it is essential that some of the more important morpho- 

 logical features of existing species should be briefly considered. 

 The additions made to our knowledge of the gameophyte^ 

 of European and tropical species during the last two decades 

 have revealed a striking diversity in habit. 



In several species, grouped round the widely distributed 

 type Lycopodium Selagohinn.,th.e comparatively short; erect or 

 suberect, shoots form fairly compact tufts ; the ordinary foliage- 

 leaves function as sporophylls, and the sporangia are not localised 

 on special portions of shoots. From this type, we pass to others 

 in which the fertile leaves tend to be confined to the tips of 

 branches, but hardly differ in form from the sterile. A further 

 degree of specialisation is exhibited by species with well-defined 

 cones composed of leaves (or bracts), the primary function of 

 which is to bear sporangia and to afford a protective covering 

 to the strobilus^ 



Lycopodium rufescens Hook. An Andian species with stout 

 dichotomously branched erect stems bears on the younger 

 shoots crowded leaves with their thick and broadly triangular 

 laminae pointing upwards, but on the older and thick shoots 

 the laminae are strongly reflexed (fig. 121, A). The lower part 

 of the specimen represented in fig. 121, A, shows tangen- 

 tially elongated scars and persistent leaf-bases or cushions 

 left on the stem after the removal of the free portions of the 

 leathery leaves, a surface-feature which also characterises the 

 Palaeozoic genus Lepidodendron. The reflexed leaves and 

 persistent leaf-cushions are clearly seen in the piece of old stem 

 of Lycopodium dichotomum Jacq., a tropical American species 



1 For Phylloglosmm, see Bertrand (82); Bower (94), (08) ; Campbell (05). 



2 Treub (84—90) ; Bruchmann (98) ; Lang (99). 

 « Sykes (08»). 



