CHARACTERS OF TRIBES AND GENERA. 167 



by A. acrostichoides and A. Stelleri, all of which are in the 

 " Species Filicum " considered as representing- one species 

 only. Many other species have been added from time to 

 time to this genus, but, on account of their having a spe- 

 cially well-defined indusium, are now most of them referred 

 to the genera Cheilanthes and Pellcea, several of which, such 

 as Pellcea marginata and P. angmtifolia, have a strong 

 claim in habit to be associated with Allosorus. Their 

 special indusium however marks them as being distinct, the 

 terminal oblong sori of Allosorus indicates its relationship 

 to be with Gymnogramma. 



Sp. A. crispus, Bernh. (v v.) ; A. Brunoniana, Wall. ; 

 A. acrostichoides, R. Br. ; A. Stelleri, Rupr. (Pteris gracilis, 

 Micnx ) ; A. glauca, Cav. (Pellcea hirsuta, Hook. Syn. Fil.). 



OBS. The last two species are placed under Pellcea in 

 the " Synopsis Filicum." See observation under Pellcea 

 for my reason for placing them here. 



77. JAMESONIA, Hook, and Grev. (1831). 

 Hook. Sp. Fil. 



Vernation sarmentose, slender, elongating, naked, sub- 

 hypogeous, Fronds short stipate, distant, linear, pinnate, 

 erect, 1 to 1 foot long, rigid, densely covered with tomen- 

 tose articulate hairs when young ; pinnae numerous 

 subrotund, J to \ inch long, coriaceous, short petiolate, 

 generally deflexed, contiguous and imbricate, margin 

 re volute, indusaeform. Veins flabellately forked. Sporangia 

 occupying the lower part of the venules, forming short 

 sori, which become confluent into one central sorus, covered 

 with crinoid jointed hairs, and partially hid by the indusae- 

 form margin. 



Type, Pteris imbricata, Cav. 



