296 ORDER 46. LEGUMINOS^E, 



12 P. nana DC. Low, ascending ; Ivs. obovate and spatulate, mostly radical ; 

 heads ovate, becoming oblong, dense ; wings lanoe-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, dispro- 

 portionately 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 Ivs. few 

 (small), spatulate, cauline oblong -linear ; seed oval, carunded. Swamps, Del. to 

 Fla. and La. This and the next are species of singular aspect. St. If 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 ; Ivs. mostly 

 radical, linear, pointed, crowded; stem Ivs. 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. ranched above, erect ; Ivs. 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. 



/?. AMBIGUA. Branches filiform, alternate ; lower Ivs. -verticillate, upper alter- 

 nate ; spikes elongated, with the fls. scattered ; seed exactly as in a. Dry 

 fields and woods, Mass, to Tenn. 



16 P. Boykinii Torr. & Gr. Sts. erect from an ascending base, simple ; Ivs. 

 obovate and lanceolate ; whorled, a few of the upper h'near and alternate ; spike 

 slender, pointed, dense ; wings, roundish, concave ; caruncle f 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; Ivs. 

 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 sphagnoua svvarnps 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. 



J3. 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 ; Ivs. 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 If 

 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. 



ORDER XLVI. LEGUMINOS^E. LEGUMINOUS PLANTS. 



Herbs, shrubs, or trees. Leaves alternate, usually compound, margins entire. 

 Stipules 2, at the tumid base of the petiole. Stipels commonly 2, Sepals 5, more 

 or less united, often unequal, the odd one always anterior. Petals 5, either papilio- 

 naceous or regular, perigynous, the odd one (when present) posterior. Stamens 



