110 OUR NATIVE FERNS AND THEIR ALLIES. 



6. P. reptans D. C. Eaton. Rootstock short, creeping; 

 stipes 3' 10' long, clustered, gray-stramineous, slender, naked ; 

 fronds 4' 12' long, membranous, softly hairy with branched or 

 stellate hairs, oblong-lanceolate, pinnate with nearly or quite 

 sessile, oblong, crenately pinnatifid pinnae, the apex pinnatifid, 

 often elongate and rooting; veins pinnate, simple, the basal 

 veinlets often anastemosing; sori on the middle of the veinlets, 

 rather small, sometimes with a minute rudimentary indusium. 

 (Polypodium reptans Swz., Aspidium reptans Mett.) On cal- 

 careous rocks, on left bank of Withlacoochee River, 15 miles 

 N.E. from Brooksville, Florida (J. Donnell Smith). 



XX. ASPIDIUM Swz. SHIELD-FERN. 



Sori round, borne on the back or rarely at the apex of the 

 veins. Indusium flat or flattish, orbicular and peltate at the 

 centre, or cordato-reniform and fixed either centrally or at the 

 sinus. Stipe continuous with the rootstock. Name from Gr. 

 aajiidioy, a small shield. A cosmopolitan genus containing 350 

 or more species. 



? i. Eu ASPIDIUM. Veins anastomosing copiously. 



1. A. trifoliatum Swz. Stipes tufted, i or more long, 

 brownish, scaly at base; fronds 12' 18' long, 6' 12' broad, 

 with a large ovate-acuminate terminal pinna narrowed or forked 

 at the base, and one or two lateral ones on each side, the lowest 

 mostly forked ; primary veins distinct to the margin ; areolae 

 fine, copious, with free included veinlets; sori in rows near the 

 main veins; indusia orbicular, peltate. Florida, Western 

 Texas. 



2. CYRTOMIUM Presl. Indusium peltate; fronds simply 

 pinnate with broad pinncs; veinlets usually uniting slightly near 

 the margin. 



2. A. juglandifolium Kunze. Stipes tufted, clothed below 

 with large scales; fronds 6' 2 long, coriaceous; pinnae 2 12 

 pairs, short-stalked, ovate-oblong or broadly lanceolate, the ter- 

 minal one distinct, and in small fronds the largest, appressed- 

 serrulate, smooth on both surfaces ; veins pinnate, the veinlets 

 few, free or uniting near the margin ; sori scattered in several 

 irregular rows. Western Texas, Arizona. 



3. POLYSTICHUM Roth. Indusium orbicular and entire, 



