17 



obliquis, immersis, crassissimis, lobos ad apicem percurren- 

 tibus, indivisis vel rarius furcatis. Soro uno in quaque pin- 

 nula — vel in pinnulis basalibus superioribus interdum binis 

 — lobum basalem anteriorem occupante, basi parenchymate 

 marginato; involucro urceolato, ore integro vel interdum 

 indistincte bilabiato; receptaculo breviter exserto. 



Madagascar : Humblot n^ 451. (Muséum d'Hist. naturelle, 

 Paris). 



The type-number of this new species was referred by 

 Baker (Journ. Bot. 1884, p. 140) as a variety to T. rigi- 

 dum Sw., from which species it certainly is abundantly 



Fig. 5. Triehomanes pachyphlebium n. sp. a, Pinna from the middle of the 



leaf, nat. size; b, two pinnulae, X2; c, fragment showing venation; d, sorus, 



more magnifîed. — C. Chr. del. 



différent, althougb belonging to the same group of species. 

 From ail the numerous forms referred to T. rigidum it 

 différa very much by its very thick and close veins and 

 its very thick texture. In thèse characters it agrées very 

 closely v/ith the American T. elegans Hich. to which our 

 species is intimately related, but T. elegans has an ovate 

 lamina v^^ith the basai pinnse the largest, it is dark green 

 and its rachis is rather broadly winged, while T. pachy- 

 phlebium has the basai pinnse somewhat shortened, is light 

 green and its rachis is very narrowly margined only by a 

 foliaceous wing. It is also less divided with the tertiary 

 lobes as a rule entire — in T. elegans deeply cleft, but 

 notw^ithstanding thèse différences the v^hole aspect of the 

 plant and ail essential characters agrée so closely with T. 

 elegans that the two species must be grouped together into 

 a spécial group, which Van den Bosch has named DavalU- 



