226 XLVII. LEGUMINOSAE. TRIFOLIUM. 
from the stem, petiolules scarcely 2/’ long. Spicate racemes terminal, solitary 
or fascicled, 3—4’ long. Vexillum purple, emarginate. Jn. 
2. A. caANESCENS. Nutt. Lead Plant. | 
Sufiruticose and canescently villose ; fts. small, numerous, and crowded, 
ovate-elliptical, subsessile, mucronate; spikes aggregate; fls. subsessile; cal. 
teeth equal, ovate, acute; vex. bright blue; leg. 1-seeded.—A beautiful species, 
2—4f high, in dry, sandy soils! Wis. to La. and Rocky Mts., and is supposed 
to prefer localities of lead ore. Leaves2—3’long. Leaflets coriaceous, 16—24 
pairs, obtuse at base, 4—6” by 1—2"”. Spikes 2—3/ long. Jl. Aug. 
16. DALEA. 
In honor of Thomas Dale, ar English botanist of the last century. 
Calyx subequally cleft or toothed ; petals unguiculate, claws of the 
wings and keel adnate to the staminate tube half way up; vexillum 
free, the limb cordate; stamens 10, united into a cleft tube; ovary 2- 
ovuled ; legume enclosed in the calyx, indehiscent, 1-seeded.— Mostly 
herbaceous and glandular-punctate. Lvs. odd-pinnate. Stipels 0, stipules 
minute, setaceous. Spikes mostly dense. 
D. aropecuréipes. Willd. (D. Linnzi. Michz. Petalostemon. Ph.) 
Glabrous and much branched; /fts. 8—14 pairs, linear-oval, obtuse or 
retuse, mucronate, punctate beneath; spikes pedunculate, oblong-cylindric, ter- 
minal, silky; bracts about equaling the acuminate segments of the calyx.—q@) 
Prairies and bottoms, Ill.! Mo., Car. Plant about 2f high, bushy and leafy and 
pale green. Leaflets not more than 4’ by 1”, sessile, and nearly in mutual 
contact. Spikes 1—2/ long. Vexillum white, wings and keel pale violet. 
17. PETALOSTEMON. Michx. 
Alluding to the union of the petals and stamens. 
Calyx 5-toothed, nearly equal; petals 5, on filiform claws, 4 of 
them nearly equal, alternate with the stamens and united with the 
staminate tube; stamens 5, monadelphous; tube cleft; legume 1- 
seeded, indehiscent, included in the calyx.—4 Lws. unequally pinnate, 
ex-stipellate. Els. in dense, pedunculate, terminal spikes or heads. 
1. P. canpipum. Michx. (Dalea. Willd.) . 
Glabrous, erect; Jfts. 7—9, all sessile, linear-lanceolate, mucronate, 
glandular beneath; spikes on long peduncles; bracts setaceous; vex. broadly 
cordate, the other petals ovate——A fine-looking plant, in dry prairies Southern 
and Western States! Stem 2—4f high, sparingly branched, slender. Leaflets 
9—18” by 3—5’, terminal one largest. Flowers small, white, crowded in dense 
spikes which are 1—3! long. Jl. 
2. P. viouaceum. Michx. (Dalea. Willd.) 
Minutely pubescent, erect; /fts. 5, linear, glandular beneath; spikes 
pedunculate, oblong or subglobose; vex. cordate, the other petals oblong, obtuse 
at base.—A beautiful plant, of similar habits with the last. Stem slender, stri- 
ate, subsimple, 13—2f high. Leaflets about 1’ by 1”, all sessile. Spikes 1—8, 
very dense, 4—14’ long. Petals of a bright violet purple. Jl. Aug. 
a 18. TRIFOLIUM. Tourn. 
Gr. rpipuddor, (three-leaved) ; Lat. trifoliwm ; Fr. trefle; Eng. trefoil. 
Calyx tubular or campanulate, 5-toothed, persistent; petals more 
or less united at the base, withering ; vexillum reflexed ; ale oblong, 
shorter than the vexillum; carina shorter than the alz; stamens 10, 
diadelphous (9 & 1); legume short, membranous, mostly indehiscent, 
covered by and scarcely longer than the calyx, 2—4-seeded; seeds 
roundish.— Herbs. Lvs. palmately trifoliate ; Ifts. with straight, scarcely 
reticulated veins. Flowers in dense heads or sptkes. 
