556 INTRODUCTION TO CEYPTOGAMIC BOTANY. 



receptacle of the sporangia is sometimes obscure or obsolete ; 

 sometimes, however, it is decidedly present. The species vary 

 in the form of the leaves, the number of the appendages, and 



Fig. 123. 



Mass from the Antheridium of Azolla rubra. From a specimen given 

 to me by Dr. Hooker. 



the minute details of the antheridia and their contents They 

 are mostly tropical and sub-tropical, extending, however, to 

 New Zealand and Tasmania in the south, and to New Yoik 

 and Ohio in the north. 



V. LycopodiacejE, D. G. 



Ltcopodine^, Swartz, &c. 



Sporangia bi-tri- valvular, unilocular, axillary, very rarely 

 multilocular, containing large spherico-tetrahedral spores ; an- 

 theridia closely resembling the sporangia, filled with minute 

 free bodies, resembling the spores in form which ultimately 

 produce spermatozoids. 



637. The greater part of the Club-mosses are distinguished, 

 in consequence of their linear leaves, by a habit resembling 

 that of Conifers ; and in many details of the fruit, there is a 

 very close analogy between the two orders, though, as I hope 

 has been satisfactorily proved above, there is no real affinity 

 between them. As, however, amongst Conifers there are 

 species with broad leaves, departing greatly from mere normal 

 forms, so in these Cryptogams there are broad-leaved Lyco- 

 'podia ; while in Tonesipteris, the coniferous habit has almost 

 vanished. Phylloglosswm (Fig. 118), though a true Lycopod, 



