llXlii. GEJTEBA OJ PEBNS : 



from a central costa, prominent ; or rarely, uniform ; venules and 

 veinlets compoundly anastomosing in (about two or three series 

 of) irregular or nearly equal-sided areoles, from the ultimate 

 of which proceed free divaricate included veinlets. 



Fronds simple pinnate or bi-pinnate, herbaceous. Rhizome 

 short, erect or decumbent. This genus cannot be very exactly 

 distinguished from Sagenia. Generally, the species of Aspidium 

 have the venation more compoundly branched; and their sori 

 are almost always compital or medial, but here and there 

 terminal sori appear. The indusium affords the best means of 

 discriminating them, but this becomes lost or difficult of ob- 

 servation in old specimens ; besides which, in some of the species 

 of Sagenia, its sinus is indistinct. It is therefore probable that 

 some species we may include in our enumeration of Aspidium, may 

 really belong to Sagenia, as here understood. We do not find, 

 however, any other intelligible, or tolerably constant way of dis- 

 tinguishing them. On the other hand, we cannot consent to 

 unite the species having reniform and peltate indusia, which 

 would involve the necessity of also uniting Lastrea with Poly- 

 stichum. The name Aspidium has been well applied to this group 

 by Schott, for though both orbicular and reniform indusia were 

 included by Swartz, under the terms umbilicate and dimidiate, 

 the former as first mentioned may be taken as typical. 



Ex. : A. singaporianum, Wall. I A. trifoliatum, Ste. 



A. calcareum, Pretl. \ A. platyphyllum, Prtl. 



115. CYRTOMIUM, Pretl, Tent. Pterid. 86. 



PHANBBOPHLEBIA, Pretl; AMELIA, Pretl; ABPIDII sp., Anct.; POLY- 

 PODII sp., Auct. 



Sori indusiate, globose, in several series parallel to the costa ; 

 the receptacles medial on the excurrent free or anastomosed 

 venules or veinlets, rarely terminal near the margin. Indusium 

 orbicular, peltate. Veins pinnate-furcate, from a central costa ; 

 the lower anterior venules free, the rest angularly and irregularly 

 anastomosing, forming unequal sub-hexagonal areoles, within 

 which are produced 13 excurrent veinlets; or, the upper 

 venules only, angularly anastomosing. 



