103. SELAGINELLA. 59 



1. MONOSTELICAE. Stems traversed by 12 steles. 



a. Homoeostachys. Sporophylla rather isomorphous, the 

 spikes therefore quadrangular (tetrastichous), as broad as 

 thick. 



1. Rotulantes. Small or middle-sized species with densely 

 tufted or radiating branches liable to curl up in drought 

 and placed at the apex of a short or elongated trunk- 

 like main stem rooting at the base only. 



2. Decumbentes. Small species, often densely caespitose; 

 shoots trailing, or ascending from a decumbent base or 

 main stem; stems mostly under 3 U mm. thick, not 

 pubescent; root-fibres often extending to the higher nodes. 



3. Radicantes. Large or middle-sized species ; shoots more 

 or less decumbent or ascending from a decumbent base, 

 branched down nearly or quite to the base; stems 

 mostly more then 3 A mm. thick, not pubescent; root- 

 fibres extending to the central and often to the higher 

 nodes; leaves heteromorphous on both stem and branches. 



4. Ascendent e*. Large or middle-sized species; shoots 

 erect, or ascending from a decumbent base, branched 

 down nearly or quite to the base, or the lower part 

 unbranched, stipitiform; stems more then 3 A mm. thick, 

 not pubescent; root-fibres confined to the base or extending 

 to a little beyond the place where the branching begins; 

 leaves heteromorphous on both stem and branches 0). 



5. Caulescentes. Large or middle-sized species; shoots 

 erect, or ascending from a decumbent base, sometimes 

 springing from a divaricating-scandent main stem, the 

 upper part branched, the lower V % part simple, 

 stipitiform ; stems more then 3 A mm. thick, not pubescent; 

 root-fibres confined to the unbranched portion, often to 

 the base only; at least the leaves of the lower half of 



C 1 ) This group is intermediate between the preceding and the folio-wing, and it 

 is often very difficult to determine whether a species of this group would not be 

 better treated as belonging to, or has not been erroneously placed in, the former or 

 the latter; the species with stipeless or short-stalked shoots differ from the preceding 

 group in having radially organized subterraneous nodes with rather isomorphous 

 leaves (conf. Hieron.). 



