Part 6

Allosorus ternifolius, Kunze, in Linnæa, xxiii., p. 220.

Pteris subverticillata, Swartz, Syn. Fil., p. 103.—Willdenow, Sp. Pl., v., p. 375.

Hab.—Texas, Trécul, No. 1334, according to Fournier. New Mexico, Wright, according to Hooker in Filices Exoticæ. The only specimens from Texas which I have of this species were collected by Dr. Sutton Hayes, near the headwaters of the Rio Colorado of Texas. It is a common Mexican species; it is found as far South as Peru, and reap pears in the Hawaiian Islands.

Description:—This belongs to the same group of species as P. Wrightiana, brachyptera and Ornithopus. It has the same nodose and scaly root-stock, dark and polished stalk, glaucescent frond and mucronulate pinnules. In Mexico, South America and the Hawaiian Islands it never occurs with more than trifoliolate pinnules, and this is perhaps the best reason for considering P. Wrightiana a distinct species. The pinnæ are tripartite rather than trifoliolate, while in the other fern just referred to, when trifoliolate the odd pinnule is more distinct and usually stalked, a distinction indicated by Hooker, but for which I am more indebted to the accurate discrimination of Mr. Faxon. In more southern localities the fronds are considerably larger than Dr. Hayes’ specimens, and the segments of the pinnæ ampler. In very dry seasons the pinnæ are considerably deflexed. The spores are trivittate as in the related species.

PELLÆA ATROPURPUREA, Link. Clayton’s Cliff-Brake.

Pellæa atropurpurea:—Root-stock short, knotted, chaffy with very narrow long-pointed soft cinnamon-brown scales; stalks four to eight inches high, terete, wiry, dark-purple or reddish-black, polished or more or less pubescent with paleaceous hairs; fronds six to twelve inches long, ovate or oblong-lanceolate in outline, evergreen, sub-coriaceous, pinnate, usually twice pinnate near the base; rachises smooth or hairy; pinnæ four to twelve pairs, the lower ones long-stalked, and divided into five to nine pinnules; upper pinnæ and the pinnules nearly sessile; oval to linear-oblong, at the base truncate or sub-cordate or sometimes hastate, obtuse or obtusely mucronulate, terminal ones longest; veins obscure, mostly twice forked; involucre rather broad, formed of the continuously recurved margin, paler and membranaceous on the edge, not fully covering the ripened sporangia.

Pellæa atropurpurea, Link, Fil. Hort. Berol., p. 59.—Fée, Gen. Fil., p. 129.—Hooker, Sp. Fil., ii., p. 138.—Eaton, in Chapman’s Flora, p. 589; Gray’s Manual, ed. v., p. 660; Ferns of the South-West, p. 319.—Lawson, in Canad. Naturalist, i., p. 272.—Hooker & Baker, Syn. Fil., p. 147.—Fournier, Pl. Mex., Crypt., p. 119.—Williamson, Ferns of Kentucky, p. 52, t. 12.

Pteris atropurpurea, Linnæus, Sp. Pl., p. 1534.—Michaux, Fl. Bor.-Am., ii., p. 261.—Swartz, Syn. Fil., p. 106.—Schkuhr, Krypt. Gew., p. 93, t. 101.—Willdenow, Sp. Pl., v., p. 375.—Pursh, Fl. Am. Sept., ii., p. 668.

Platyloma atropurpureum, J. Smith.—Torrey, Fl. New York, ii., p. 488.

Allosorus atropurpureus, Kunze, in Sill. Journ., July, 1848, p. 86; Linnæa, xxiii., p. 218.—Gray, Manual, ed. ii., p. 591.—Mettenius, Fil. Hort. Lips., p. 44.

Pellæa mucronata, Fée, 9me Mém., p. 8.

Pellæa glabella, Mettenius & Kuhn, in Linnæa, xxxvi., p. 87.

Pteris spiculata, Schkuhr, Krypt. Gew., p. 92, t. 100.

Pteris Adianti facie, caule ramulis petiolisque politiore nitore nigricantibus, etc., Gronovius, Fl. Virginica, ed. i., p. 197.

Hab.—Crevices of shaded calcareous rocks; from Canada to the Rocky Mountains of British America, and southward to Alabama, Arkansas, Indian Territory and Arizona. It has been found in several parts of Mexico, and even in South America (“Andes of Mecoya, Pearce,” according to Synopsis Filicum). It was collected by John Clayton about 1736, “on the shore of the river Rappahannock in a shady place by the root of a juniper near the promontory called Point Lookout,” and I take pleasure in giving it an English name in his honor.

Description:—The root-stock of this fern is rather short, usually somewhat nodose, and densely chaffy with very narrow long-pointed soft bright-brown scales, which in the specimens examined are destitute of midnerve.

The stalks are rigid and wiry, terete, nearly black in color, but with a slight reddish tinge, and usually more or less pubescent with very narrow chaffy hairs, which are often more abundant and harsher along the rachises, making them almost hirsute. Pellæa glabella was founded on specimens from Missouri and the North-West, which had the stalk perfectly smooth, and the chaff of the root-stock a trifle wider than usual. The section of the stalk shows a single U-shaped fibro-vascular bundle, and a strong outer sclerenchymatous sheath.

The fronds are developed late in the Spring, and remain green through the next Winter. They are almost coriaceous in texture, smooth and dark-bluish-green above, paler, and sometimes slightly chaffy beneath. They are from a few inches to about a foot in length, and vary in outline from ovate to oblong-lanceolate. In seedling plants the earliest fronds are round-cordate, the next cordate-ovate, and then follow trifoliate, pinnate, and finally mature bipinnate fronds. The largest fronds have about five pairs of compound pinnæ, each with from three to eleven pinnules, and above these are from four to six pairs of simple pinnæ, besides the terminal one, which is often the longest of all.

The pinnules and the simple pinnæ of the sterile fronds are commonly oval, and not more than half an inch long, but those of the fertile fronds are narrower and longer, sometimes nearly two inches long. The base is either truncate or slightly cordate; sometimes where there is a transition from compound to simple pinnæ, a pinna will be found conspicuously auricled on both sides, or on the upper side only. Forked pinnules are occasionally seen.

The margin is continuously recurved to form a rather broad involucre, and the very edge is somewhat thinner and whiter. The veins are pinnately arranged on both sides of the midvein, and fork about twice before reaching the margin. The upper part of the veinlets is covered with sporangia, which as they ripen push out from beneath the involucre. The spores are obscurely tetrahedral and trivittate, as in the other species of the genus.

This fern very often grows in company with Camptosorus rhizophyllus, and its root-stock is often hidden beneath mosses of the genus Anomodon: it takes kindly to cultivation, especially if it be planted in the crevices of calcareous rock-work. It may occur on other than calcareous rock, but I have never seen it on either granite, sandstone or basalt.

Names for varieties of this species have been proposed by Pursh, and by Fournier, but the characters assigned do not seem sufficiently distinctive.

PELLÆA GRACILIS, Hooker. Slender Cliff-Brake.

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.