8 P. Nuttallii Torr. & Gr. St. erect, somewhat fastigiate; lvs. linear; spikes acute, roundish-oblong, dense; wings elliptical, attenuate at base; crest minute; caruncle notched, lateral on the thick seed stipe. - Mass., R. I., to La. St. 6 to 10' high, the branches overtopping the stem. Lvs. 6 to 8" by 1", acute. Spikes 5 to 7" long, 3 to 4" diam. Wings of the calyx rose-red. Seeds black, pear-shaped. Aug. (P. sanguinea Nutt.)
9 P. fastigiata Nutt. Slender and much branched above; lvs. linear; spikes roundish, loose-flowered; wings ovate-oblong, distinctly clawed; caruncle broad, nearly embracing the small seed-stipe (immature). - N. J. to Fla in dry soils. St. 8 to 12' high. Lvs. 8 to 12" long, 1" wide, acute. Spikes about 5" diam., the fls. distinctly pediceled, and of a brighter rose-color than the foregoing. (P. sanguinea T. & G.)
10 P. sanguinea L. St. branching at top; lvs. linear and lance-linear, spikes oblong, obtuse, dense; wings oval or ovate, obtuse, subsessile; caruncle mostly simple, nearly as long as the hairy seed. - An erect plant, 6 to 12' high, found in meadows and wet grounds, Mass. to La. St. angular, with fastigiate branches, each ending in a smaller spike than that of the main stem, but often overtopping it. Lvs 1' long, 1 to 2" wide. Heads about 6" thick. The caruncle is double in a few of the seeds, with divergent segments. Fls. purple, caducous. Jl. - Oct. (P. purpurea Nutt.)
11 P. lutea L St. mostly simple; root lvs. spatulate, obtuse, attenuate at base; cauline ones lanceolate, acute; rac. ovate-globous, obtuse, dense; fls. pedicillate; wings ovate, mucronate, keel with a minute crest. - Sandy plains, N. J. to Fla. St. 8 to 13' high, generally many from the same root, seldom with a few spreading branches. Fls. orange-yellow, longer than the bracts, aggregated in one terminal roundish head which is 8 or 9" thick. A showy plant.
12 P. nana DC. Low, ascending; lvs. obovate and spatulate, mostly radical; heads ovate, becoming oblong, dense; wings lance-ovate, cuspidate-acuminate twice longer than the slightly crested keel. - S. States, in pine woods, common. Sts. 3 to 5' high. Lvs. 1 to 2' long, rosulate. Head often near 1' thick, disproportionately large, the fls. citron-yellow, changing to green. Apr., May.
13 P. ramosa Ell. Erect, corymbously branched above; spikes loose, oblong, numerous, forming one or more dense, level-topped cymes; radical lvs. few (small), spatulate, cauline oblong-linear; seed oval, caruncled. - Swamps, Del. to Fla. and La. This and the next are species of singular aspect. St. 1f high. Lvs. about 6' long, few at the root. Spikes about 4" diam., the fls. greenish yellow, becoming finally dark green. Fls. pedicelled. Jn. - Aug. (P. corymbosa Nutt.)
14 P. cymosa Walt. Sts. tall, simple, corymbously branched at top; lvs. mostly radical, linear, pointed, crowded; stem lvs. very few, linear-subulate; racemes spike-like, numerous, forming a dense, fastigiate cyme; seed globular, naked.- Swamps, in the pine woods, N. Car. to Fla. Sts. often many from the same root, 2 to 4 or 5f high. Lvs. grass-like, 2 to 3' long, forming a dense tuft at base. Fls. pedicelled, greenish yellow, becoming finally greenish-brown. Jn. - Aug. (P. attenuata Ell. graminifolia Poir. acutifolia T. & G.)
15 P. verticillata L. St. branched above, erect; lvs. linear, verticillate both on the stem and opposite branches; spikes slender, stalked; fls. alternate, crested; calycine wings roundish; seed oblong, smooth, caruncle hardly half as long.- Found on dry hills, U. S. and Can. St. very slender, square, 6 to 8' high. Lvs. in whorls of 5 or 6, 4 to 10" long, 1" wide. Fls. small greenish-white, in racemes 3 to 10" long, which are higher upon the branches than upon the main stem. Jl. - Oct.
β. ambigua. Branches filiform, alternate; lower lvs. verticillate, upper alternate; spikes elongated, with the fls. scattered; seed exactly as in a. - Dry fields and woods, Mass. to Tenn.
16 P. Boykinii Torn & Gr. Sts. erect from an ascending base, simple; lvs. obovate and lanceolate; whorled, a few of the upper linear and alternate; spike slender, pointed, dense; wings, roundish, concave; caruncle § the length of the very hairy seed. - Ga. and Fla. Sts. slender, several from the same root, 12 to 18' high. Lvs. 6 to 12" long, in 3s, 4s, and 5s. Fls. whitish, the wings green, with white borders. Jn., Aug.
17 P. cruciata L. St. erect, somewhat fastigiate, winged at the angles; lvs. verticillate in 4s, linear-oblong, punctate, spikes ovate, dense, obtuse, sessile or nearly so; seed ovate, smooth, caruncle fully as long; wings deltoid-ovate, cuspidate. - In sphagnous swamps and other low grounds, Mass. to Fla. and La. St. 3 to 12' high, very slender, smooth, slightly winged at the 4 angles. Lvs. 2 to 10" or more long, 1 to 2" wide (upper ones largest), obtuse, tapering to the base, with small, resinous dots. Spikes capitate, 5" thick. Wings greenish-purple, much dilated at base. Jl., Aug.
β. cuspidata. Lvs. linear; heads larger, oblong, squarrous with the elongated cusps of the wings. This is the more common southern form. (P. cuspidata Hook.)
18 P. brevifolia Nutt. Slender, branched above; lvs. linear, short, remote, in 4s, or on the branches scattered; spike oblong, dense, obtuse, on long peduncles; wings ovate-lanceolate, acute; seed just as in No. 17. - N. Y. to Fla. About 1f high. Heads 4" thick, 1 to 2' long (as appears from the squarrous rachis). Lvs. 6 to 9" long. Fls. roseate. Aug., Sept
P. Baldwinii Nutt. of S. E. Georgia is unknown to the author, unless it be a variety of P. ramosa, differing in its more dense heads of greenish-white flowers.