PTERIDOPHYTA 



A. LYCOPODIN^E 



Heterosporous Type 



SELAGINELLA MARTENSII 



SPOROPHYTE 



I. This plant is commonly grown in green-houses, and 

 specimens can be readily obtained from nurserymen. In a well- 

 grown plant note with the naked eye the following external 

 characters : 



1. The stem ascending, frequently branched, apparently in a 

 dichotomous, but really in a monopodial manner : the branch- 

 ing occurs only in a single plane. 



2. The leaves, of small size, and simple inform, with aciliate 

 margin, and arranged in alternating pairs : each pair consists 

 of a dorsal and a ventral leaf, the whole series thus forming 

 four orthostichies : note the two different sizes of leaves 



a. The larger ventral leaves, arranged in two orthostichies, 

 and without terminal awns. 



b. The smaller dorsal leaves, also arranged in two 

 orthostichies, each leaf being terminated by a fine awn. 



Each leaf has a single central nerve or midrib. Turn back 

 one of the leaves, and observe with a lens the small scale-like 

 ligule. 



3. The rhizophores, long cylindrical branched organs, which 

 arise at the points of branching of the obliquely ascending stem, 

 and grow vertically downwards : note their frequent bifurcations. 



