9. J. trífidus, L. Stems densely tufted from matted creeping rootstocks, erect (5–10´ high), sheathed and mostly leafless at base, 2–3-leaved at the summit, the upper thread-like leaves subtending the sessile head; flowers brown (1½–2´´ long); sepals ovate-lanceolate, acute, equalling or rather shorter than the ovate beak-pointed deep brown capsule; anthers much longer than the filaments; seeds few, oblong, angled (1´´ long), short-tailed.—Alpine summits of N. Eng. and N. Y., and far northward; also in N. J. (Eu.)
[+][+] Leaves flat and grass-like; stamens 3; stems flattened, simple, leafy.
10. J. rèpens, Michx. Stems ascending (4–6´ high) from a fibrous annual root, at length creeping or floating; leaves short, linear, those of the stem nearly opposite and fascicled; heads few in a loose leafy panicle, 3–12-flowered; flowers green (3´´ long); sepals rigid, lance-subulate, slender-pointed, the 3 outer as long as the linear triangular obtuse capsule, the inner much longer; stamens as long as the outer sepals; filaments many times longer than the oblong anthers; seeds small ({1/5}´´ long), obovate, slightly pointed, very delicately ribbed and cross-lined.—Miry banks, Md. to Fla. and La.
11. J. marginàtus, Rostk. Stem erect, from a bulbous and stoloniferous base (1–3° high); leaves long-linear; heads 3–8-flowered, panicled; flowers purplish with green (1½´´ long); sepals oblong, the 3 outer acute and slightly awned, the inner longer, mostly obtuse, as long as the almost globular scarcely mucronate capsule; stamens exceeding the outer sepals; purple anthers shorter than the filaments; style very short; seeds (¼–{1/3}´´ long) slender, pointed at both ends and strongly ribbed.—Moist sandy places, S. New Eng. to Fla., west to Mich., Mo., and Tex.—Var. paucicapitàtus, Engelm., has few large 8–15-flowered heads; and var. biflòrus, Engelm., has numerous small 2–3-flowered heads in much-branched panicles.
[*][*] Flowers solitary, panicled; stamens 6.
[+] Stems slender, simple, tufted, leafy below; root perennial (fl. early in summer).
[++] Seeds tail-pointed at both ends.
12. J. Vàseyi, Engelm. Stems rigid (1–2½° high); leaves nearly terete, very slightly channelled on the inner side; panicle longer than the involucral leaf, loose; flowers few, often one-sided, greenish or light brown (2´´ long or more); sepals lanceolate, acute, appressed, shorter than the oblong and retuse green-brown capsule; anthers as long as the filaments; style very short; seeds slender (½–{2/3}´´ long), closely ribbed.—N. Maine (Pringle); Mich. to Iowa and westward.
13. J. Greénii, Oakes & Tuckerm. Stems rigid (1–2° high); leaves nearly terete, very deeply channelled (almost involute) on the inner side; panicle usually much shorter than the principal erect involucral leaf, dense, the numerous flowers often one-sided (1¾´´ long); sepals lanceolate, acute, light greenish-brown, appressed, shorter than the ovoid-oblong obtuse greenish-brown capsule; anthers as long as the filaments; style very short; seeds ovoid ({1/3}–{2/5}´´ long), ribbed and delicately cross-lined.—Sandy coast of N. Eng., N. Y., and N. J., and on the east shore of Lake Michigan.
[++][++] Seeds merely apiculate at both ends.