Aspidium. FILICES. 345 



Damp, rich woods, not rare. A common fern throughout temperate North America, Europe 

 and northern Asia, presenting very many modifications in size, shape of the frond, and cutting of 

 the pinnx and pinnules. The fully developed subtripinnate form (var. commune, Eaton) is not 

 rare in California. Var. latifolium, Hook., with broadly ovate-oblong pinnules, var. cydosorum, 

 Ruprecht, with very large and broad fronds and roundish sori, and var. cmgustum, with narrow 

 and rather rigid fronds, besides various intermediate forms, are all found within the State. 



12. PHEGOPTERIS, Fee. 



Sori roundish, minute, naked, placed on the back of the veins below their attenu- 

 ated apices. Fronds various, subtripinnate in our only species. Stalk continuous 

 with the rootstock, and not joining it by an articulation as in Polypodium. 



This genus, containing about 100 species, differs from Aspidium only in having no indusium. 

 Four species are found in North America, three of them also common to Europe. 



1. P. alpestris, Mettenius. Eootstock short and thick, erect or assurgent : 

 stalks subterminal, 4 to 10 inches long, chaffy near the base : fronds 1 to 2 feet 

 long, membranaceous, smooth, oblong-lanceolate, acuminate, pinnate with delicately 

 bipinnatiftd deltoid-lanceolate pinnae, the lower pinnae distant and decreasing mod- 

 erately ; pinnules ovate-oblong, or ovate-lanceolate, doubly incised and toothed : sori 

 small, round, usually copious on all but the lowest pinnae. Fil. Hort. Lips. 83 ; 

 Eaton, Ferns of N. Amer. i. 171, t. 23, fig. 1. Polypodium alpestre, Hoppe ; Hooker, 

 Brit. Ferns, t. 6, and Sp. Fil. iv. 251. 



Among rocks at high elevations ; top of Lassen's Peak, and on Mount Shasta, Pyramid Peak, 

 and other high peaks in the Sierra Nevada, Brewer, Lcmmon, Muir, etc. This fern often forms 

 patches of several feet in extent, as noticed repeatedly by Brewer and Lemmon. It is found also 

 in British Columbia, and in the mountains of northern and central Europe to the Caucasus. 



P. POLYPODIOIDES, Fee (Eaton, Ferns of N. Amer. ii. 217, t. 75, fig. 1 - 4). Rootstock very 

 slender, creeping : fronds 4 to 6 inches long, hairy on the veins, deltoid-ovate, bipinnatih'd with 

 obtuse lobes : rhachis interruptedly winged by the adnate basal segments of the pinnse. Said to 

 have been recently discovered near San Jose. It is a common fern in the Eastern States north of 

 Tennessee, and is found in Alaska, Greenland, Labrador, Europe, northern Asia and Japan. 



P. DRYOPTERIS, Fee, with a smooth ternate frond, primary divisions stalked and 1 -2-pinnate 

 with obtuse lobes, is an eastern and European fern, found in Oregon, but not yet in California. 



13. ASPIDIUM, Swartz. SHIELD-FERN. WOOD-FERN. 



Sori round, borne on the back or at the apex of the veinlets, the indusia round 

 and attached to the middle of the sorus by a short central stalk, or roundish-reniform 

 and attached at the base of the sinus or indentation. Veins free in the Californian 

 species, the fronds mostly large and once or twice pinnate. 



A genus embracing, as here understood, over 300 species, the greater part tropical or subtropi- 

 cal, but a few extending to the Arctic regions. Standard British works divide the genus into two, 

 corresponding with the following sections. 



1. Indusium roundish-reniform or orbicular with a narrow sinus. DRYOP- 

 TERIS. (Nephrodium, Hooker & Baker.) 



* Texture thin or membranaceous : veins simple or once forked. 



1 . A. Nevadense, Eaton. Rootstock rather stout, creeping, chaffy and covered 

 with persistent stalk-bases : fronds thin and delicate, standing in a crown, short- 

 stalked, narrowly lanceolate, 1| to 3 feet high, pinnate ; pinnae linear-lanceolate from 

 a broad and nearly sessile base, 2 to 4 inches long, deeply pinnatifid ; the lower pairs 

 distant and gradually reduced to mere auricles ; segments crowded, narrowly oblong, 

 obtuse, subentire, slightly hairy on the veins beneath and minutely resinous-dotted ; 

 veins mostly simple, the lower ones sometimes forked : sori close to the margin ; in- 

 dusium minute, glandular and sparsely pilose. Ferns of N. Amer. i. 73, t. 10. 



Moist and shady places along creeks and in mountain meadows ; Butte County (Mm. Ames) ; 

 Plumas County (Mr*. Ames and Mrs. Austin) ; Trinity County (Klccbcrgcr) ; Webber Lake, and 



