J. SMITH ON THE GENERA OF FEUNS. 183 



Species. H. Brownii, J. Sm. Illust. Hook, et Bauer's Gen. 

 Fii. t. I. 



Obs. This genus is founded upon a solitary species, and is 

 so similar in habit and venation, that without a close exami- 

 nation of its sori, it would pass for a species of Drynaria, 

 allied to D. plantaginea and D. sceptrum, and only to be dis- 

 tinguished from that genus, as also from the following, by the 

 sori being furnished with a very obscure but perfect calyci- 

 form indusium, similar in structure to that of IVoodsia, but 

 differing from that genus entirely in habit and venation. 

 This fern is a native of Trinidad. 



79. AsPiDiuM, Sw. Schoff. J. Sm. 



Feiws costaeform ; venules compoundly anastomosing, pro- 

 ducing from their sides, variously directed, free veinlets, which 

 terminate within the areoles ; sporangia produced on the 

 angles or points of confluence of veinlets, constituting round 

 sori ; indusium usually orbicular and central, rarely reniform. 



Fronds /roni 1 to ^ feet or more in height^ simple, or lobed, 

 pinnate or bipinnate, margin entire, sinuated, or laciniated; 

 sori arranged in a row on each side of the costceform veins, or 

 primary anastomosing venules, or irregular, by confluence some' 

 times oblong, 



Examp. 1. A. Singaporianum, Wall. 2. A. trifoliatum, 

 Sw. 3. A. macrophyllum, Sw. 4. A. alatum, Wall, 5. 

 A. decurrens, Presl. 6. A. repandum, Willd. 7. A. poly* 

 morphum, Wall. Illust. Schott. Gen. Fil. t. 2. Hook, et 

 Bauer Gen. Fil. t. 33. 



Obs. This genus, as now restricted, contains species ana- 

 logous in habit and venation to the Dipteris section oi Dry^ 

 naria in Polypodiece, but distinguished by the presence of 

 indusium which is usually orbicular ; but instances of both 

 orbicular and reniform indusia are often found on the same 

 frond, and sometimes the latter are the most numerous ; but 

 as the species agree in habit, they therefore cannot be sepa« 

 rated on the form of the indusia alone. 



