Part 213 (1/2)

-- 2. POLSTICHUM. _Indusium orbicular and entire, peltate, fixed by the depressed centre; fronds rigid and coriaceous, evergreen, very chaffy on the rhachis, etc.; pinnae or pinnules auricled at base on the upper side, crowded, the teeth or lobes bristle-tipped._

[*] _Fronds simply pinnate._

10. A. acrostichodes, Swartz. (CHRISTMAS FERN.) (Pl. 19, fig. 3, 4.) Frond lanceolate (1--2 high), _stalked; pinnae linear-lanceolate_, somewhat scythe-shaped, half-halberd-shaped at the slightly stalked base, serrulate with appressed bristly teeth; _the fertile_ (upper) _contracted and smaller_, bearing contiguous fruit-dots near the midrib, which are confluent with age, covering the surface.--Var. INCSUM is a state with cut-lobed pinnae, a not unfrequent case in the sterile fronds; sometimes with all the tips fertile.--Common in rocky woods, especially northward. July.

11. A. Lonchtis, Swartz. Frond linear-lanceolate (9--20' high), _scarcely stalked, very rigid; pinnae broadly lanceolate-scythe-shaped, or the lowest triangular_, strongly auricled on the upper side, and wedge-truncate on the lower, densely spinulose-toothed (1' or less in length), copiously fruit-bearing; fruit-dots contiguous and near the margins.--Woods, southern sh.o.r.e of Lake Superior, and northward. (Eu.)

[*][*] _Fronds bipinnate._

12. A. aculeatum, Swartz, var. Braunii, Koch. _Fronds spreading_ (1--2 long), oblong-lanceolate in outline, with a tapering base, the lower of the many pairs of oblong-lanceolate pinnae gradually reduced in size and obtuse; pinnules ovate or oblong, obtuse, truncate and almost rectangular at base, short-stalked, or the upper confluent, sharply toothed, beset with long and soft as well as chaffy hairs.--Deep woods, mountains of New Eng., N. Y., and Penn., and northward. (Eu.)

14. CYSToPTERIS, Bernhardi. BLADDER FERN. (Pl. 19.)

Fruit-dots roundish, borne on the back of a straight fork of the free veins; the delicate indusium hood-like or arched, attached by a broad base on the inner side (toward the midrib) partly under the fruit-dot, early opening free at the other side, which looks toward the apex of the lobe, and is somewhat jagged, soon thrown back or withering away.--Tufted ferns with slender and delicate 2--3-pinnate fronds; the lobes cut-toothed. (Name composed of ??st??, _a bladder_, and pte???, _fern_, from the inflated indusium.)

1. C. bulbifera, Bernh. (Pl. 19, fig. 1--3.) _Frond lanceolate, elongated_ (1--2 long), 2-pinnate; the pinnae lanceolate-oblong, pointed, horizontal (1--2' long); the _rhachis and pinnae often bearing bulblets underneath, wingless_; pinnules crowded, oblong, obtuse, toothed or pinnatifid; indusium short, truncate on the free side.--Shaded ravines, not rare from N. Eng. to Ark., commoner on calcareous rocks. July.--Specimens from Tenn. and Ark. have sometimes shorter fronds and few or no bulblets, indicating an approach to the next species.

2. C. fragilis, Bernh. _Frond oblong-lanceolate_ (4--8' long, besides the brittle stalk which is fully as long), 2--3-pinnate; the pinnae and _pinnules_ ovate or lanceolate in outline, irregularly pinnatifid or cut-toothed, mostly acute, _decurrent on the margined or winged rhachis_; indusium tapering or acute at the free end.--Shaded cliffs and rocky woods; common and greatly varying in the shape and cutting of the pinnules. July. (Eu.)

15. ONOCLeA, L. (Pl. 16 and 19.)

Sporangia borne on elevated receptacles, forming roundish sori imperfectly covered by very delicate hood-shaped indusia attached to the base of the receptacles. Fertile fronds erect, rigid, with contracted pod-like or berry-like divisions at first completely concealing the sporangia, and at last, when dry and indurated, cracking open and allowing the spores to escape. Sterile fronds foliaceous. Rootstocks creeping and constantly forming new plants. (Name apparently from ????, _a vessel_, and ??e??, _to close_, from the singularly rolled up fructification.)

-- 1. ONOCLEA proper. _Sterile frond with anastomosing veins._

1. O. sensibilis, L. (SENSITIVE FERN.) (Pl. 19, fig. 1, 2.) Fronds scattered; the sterile ones long-stalked (2--15' long), triangular-ovate, pinnatifid into a few oblong-lanceolate sinuately lobed or nearly entire segments; veins reticulated with fine meshes; fertile fronds contracted, closely bipinnate, the pinnules rolled up into berry-like bodies.--Moist meadows and thickets, very common and variable. July.--Imperfectly fertile fronds sometimes occur, with the still foliaceous pinnae cut into obovate segments with free veins and abortive sori; the so-called var. OBTUSILOBaTA.

-- 2. STRUTHIoPTERIS. _Sterile frond with free veins._

2. O. Struthiopteris, Hoffmann. (Pl. 16, fig. 1--5.) Fronds growing in a crown; sterile ones short-stalked (2--10 high), broadly lanceolate, narrowed toward the base, pinnate with many linear-lanceolate, pinnatifid pinnae; veins free, the veinlets simple; fertile frond shorter, pinnate with pod-like or somewhat necklace-shaped pinnae.

(Struthiopteris Germanica, _Willd._)--Alluvial soil, common northward.

July.--The rootstock sends out slender underground stolons, which bear fronds the next year. (Eu.)

16. WOoDSIA, R. Brown. (Pl. 19.)

Fruit-dots round, borne on the back of simply-forked free veins; the very thin and often evanescent indusium attached by its base all around the receptacle, _under_ the sporangia, either small and open, or else early bursting at the top into irregular pieces or lobes.--Small and tufted pinnately-divided ferns. (Dedicated to _Joseph Woods_, an English botanist.)

[*] _Stalks obscurely articulated some distance from the base; fronds chaffy or smooth, never glandular; indusium divided nearly to the centre into slender hairs which are curled over the sporangia._

1. W. Ilvensis, R. Brown. _Frond oblong-lanceolate_ (2--6' long by 12--18” wide), smoothish and green above, _thickly clothed underneath as well as the stalk with rusty bristle-like chaff_, pinnate; the pinnae crowded, oblong, obtuse, sessile, pinnately parted, _the numerous crowded segments oblong_, obtuse, obscurely crenate; the fruit-dots near the margin, somewhat confluent when old.--Exposed rocks; common, especially northward, and southward in the Alleghanies. June. (Eu.)

2. W. hyperbrea, R. Brown. Frond narrowly oblong-lanceolate (2--6' long by 8--12” wide), smooth above, sparingly paleaceous-hirsute beneath, pinnate; the pinnae triangular-ovate, obtuse, pinnately lobed, the lobes few and nearly entire; fruit-dots rarely confluent.--Mountain ravines, northern Vt. and N. Y., and northward; rare. (Eu.)

3. W. glabella, R. Brown. (Pl. 19, fig. 1--3.) _Smooth and naked throughout; frond linear_ and very delicate (2--5' high), pinnate; _pinnae roundish-ovate_, the lower ones rather remote (2--4” long), obtuse, crenately lobed; fruit-dots scanty; the hairs of the indusium fewer than in the last two species.--On moist mossy rocks, mountains of northern New Eng., north and westward. First found at Little Falls, N. Y., by _Dr. Vasey_. (Eu.)

[*][*] _Stalks not articulated; fronds never chaffy, often glandular-p.u.b.escent._