  PellÆa gracilis:—Root-stock slender, creeping, cord-like, scantily furnished with little ovate appressed scales; stalks scattered, slender, a span long or less, brownish-stramineous, somewhat shining, darker and slightly chaffy at the base; fronds two to four inches long, thin and tender, smooth, ovate or ovate-oblong, pinnate; pinnÆ few, the lower two to four pairs once or twice pinnatifid, the uppermost simple; segments of the sterile fronds adnate-decurrent, roundish-obovate, crenately lobed and toothed; those of the taller fertile fronds lanceolate or linear-oblong, and more distinct, entire or auricled, terminal ones longest; veins rather distant, mostly once forked; involucre broad and continuous, delicately membranaceous. PellÆa gracilis, Hooker, Sp. Fil., ii., p. 138, t. cxxxiii, B.—Eaton, in Gray’s Manual, ed. v., p. 659; Ferns of the South-West, p. 319.—Hooker & Baker, Syn. Fil., p. 145.—Porter & Coulter, Syn. Fl. Colorado, p. 153. Pteris gracilis, Michaux, Fl. Bor.-Am., ii., p. 262.—Swartz, Syn. Fil., p. 99.—Willdenow, Sp. Pl., v., p. 376.—Pursh, Fl. Am. Sept., ii., p. 668.—Hooker, Fl. Bor.-Am., ii., p. 264. Allosorus gracilis, Presl, Tent. Pterid., p. 153.—Torrey, Fl. New York, ii., p. 486.—Gray, Manual, ed. i., p. 624; ed. ii., p. 591, t. ix.—Parry, in Owen’s Geol. Surv. of Wisconsin, etc., p. 621.—Mettenius, Fil. Hort. Lips., p. 44. Cheilanthes gracilis, Kaulfuss, Enum. Fil., p. 209. Pteris Stelleri, Gmelin, “Nov. Com. Petrop., xii., p. 519, t. 12, f. 1.” Allosorus Stelleri, Ruprecht, Distr. Crypt. Vasc. in Imp. Ross., p. 47.—Ledebour, Fl. Ross., iv., p. 526.—Moore, Ind. Fil., p. 46.—Lawson, in Canad. Naturalist, i., p. 272. Allosorus minutus & Pteris minuta, Turczaninow, fide Moore. Hab.—Crevices of damp and shaded calcareous rocks, especially in deep glens; Labrador, Butler, to British Columbia, and southward to Iowa, Parry, Wisconsin and Pennsylvania. Also in Colorado, near Breckinridge City, Brandegee. Siberia, Tibet and the Himalayas. It is found in Sunderland, Massachusetts; at Trenton Falls, Chittenango Falls, and other deep glens in Central New York; in Lycoming and Sullivan Counties, Pennsylvania, and in other similar places in Vermont, Michigan, etc., but is by no means a common plant. Description:—This is the most delicate of all the PellÆas, and has fronds a good deal like those of Cryptogramme acrostichoides, but tenderer, and with sub-marginal fructification. The root-stock is very slender, scarcely more than half a line in thickness, and sometimes two or three inches long. It is so hidden in the crevices of the rocks that it is seldom secured by collectors. The scales are minute, appressed to the root-stock, and almost filmy in their delicacy. The stalks are scattered along the root-stock, and are generally about five or six inches long, those of the fertile fronds longer, stouter and of a darker color than the others. They are smooth and somewhat polished, but lighter in color and far more tender in consistency than in most of our other species of this genus. The fertile and the sterile fronds are unlike, though both are very delicately membranaceous, and pinnate with once or twice pinnatifid pinnÆ. The rachis is not winged in its lower half, except in very small fronds, but above the middle it is narrowly winged, as are also its divisions. The lowest one or two pairs of pinnÆ are twice pinnatifid in the largest specimens, but more commonly but once pinnatifid. In the sterile fronds the segments of the pinnÆ are very plainly adnate to the secondary midrib, and are roundish or roundish-obovate in shape. They are from three to six lines long and about two-thirds as broad. Their margin is more or less lobed and crenately toothed. In the fertile fronds the segments are more distinct, longer and narrower, measuring often six to ten lines in length and one or two in width. The terminal pinna of the frond and the terminal segments of the pinnÆ are considerably longer than the others. The veins are conspicuous, and distant, much more so than in our other species of PellÆa. They fork once about midway between the midvein and the margin, and sometimes, especially in fertile fronds, a second time just within the margin. The involucre is continuous, broad, and even more delicate Mr. Moore and some other authors are disposed to insist on the right of priority belonging to the specific name Stelleri. But the name gracilis has been used by nearly every writer on American Ferns since the time of Michaux, and will most probably be kept up rather than the other. It should be noted that Ruprecht considered his Allosorus Stelleri to be distinct from our plant, and mentions several points of difference in his work on the Distribution of Vascular Cryptogamia in the Russian Empire. The figure is taken from specimens collected in Sunderland, Hampshire County, Massachusetts, by the late Rev. David Peck. |
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