u 



ARKIV FÖR BOTANIK. BAND 1. 



authentic specimens, which occur in Herb. Swartz (the name 

 ipusilUim» written by Swartz's own hand). This plant is of 

 the same type as Tr. reptans Sw., but pecnliar as to its mi- 

 nute fronds, even in a fertile state — only 1-2 cm in length — , 

 and recognized by copious marginal hairs (this mark is al- 

 ready pointed out by Swartz). Sterile fronds remain linear- 

 oblong and almost entire. Becoming fertile, they grow some- 

 what broader, spathulate or obovate, and more or less pin- 

 natifid with a few patent lobes; such a frond has sometimes 





/fj 



^^fym. 





B 



Fig. 20. Trichomanes pusillum Sw.. the original specimen from Jamaica 



in Herb. Swartz (Stockholm), A plants of ditferent development (natural 



size): B cellular structur of a fertile frond (centre. X 110); C margin of a 



little sterile frond (X 110). 



in the youngest state an almost orbicular blade, but is distin- 

 guished from Tr. sphenoides (the following species) by the 

 almost branchless veinlets, tig. 21 (compared with fig. 22, 23). 

 The secondary veins and veinlets are very numerous, 

 extremely slender and much more crowded than in Tr. reptans. 

 In a young frond the venation is nearly simply ])innate, great- 

 er part of the secondary veins being branchless, and the 



