[*][*][*] Annuals with at least the lower stem-leaves whorled in fours, sometimes in fives; spikes terminating the stem and branches; fl. summer and autumn.
[+] Spikes short and thick (4–9´´ in diameter); bracts persisting after the fall of the (middle-sized) rose or greenish purple flowers; crest small.
10. P. cruciàta, L. Stems (3–10´ high) almost winged at the angles, with spreading opposite branches; leaves nearly all in fours, linear and somewhat spatulate or oblanceolate; spikes sessile or nearly so; wings broadly deltoid-ovate, slightly heart-shaped, tapering to a bristly point or rarely pointless; caruncle nearly as long as the seed.—Margin of swamps, Maine to Va. and southward near the coast, and west to Minn. and Neb.
11. P. brevifòlia, Nutt. Rather slender, branched above; leaves scattered on the branches, narrower; spikes peduncled; wings lanceolate-ovate, pointless or barely mucronate.—Margin of sandy bogs, R. I., N. J. and southward.
[+][+] Spikes slender (about 2´´ thick), the bracts falling with the flowers, which are small, greenish-white or barely tinged with purple, the crest of the keel larger.
12. P. verticillàta, L. Slender (6–10´ high), much branched; stem-leaves all whorled, those of the (mostly opposite) branches scattered, linear, acute; spikes peduncled, usually short and dense, acute; wings round, clawed; the 2-lobed caruncle half the length of the seed.—Dry soil; common.
Var. ambígua. Leaves (and branches) all scattered or the lowest in fours; spikes long-peduncled, more slender, the flowers often purplish and scattered. (P. ambigua, Nutt.)—N. Y. to Mo., and southward.
[*][*][*][*] Biennials or annuals, with alternate leaves, and yellow flowers, which are disposed to turn greenish in drying; crest small; flowering all summer.
13. P. lùtea, L. Low; flowers (bright orange-yellow) in solitary ovate or oblong heads (¾´ thick) terminating the stem or simple branches; leaves (1–2´ long) obovate or spatulate; lobes of the caruncle nearly as long as the seed.—Sandy swamps, N. J. and southward, near the coast.
14. P. ramòsa, Ell. Flowers (citron-yellow) in numerous short and dense spike-like racemes collected in a flat-topped compound cyme; leaves oblong-linear, the lowest spatulate or obovate; seeds ovoid, minutely hairy, twice the length of the caruncle.—Damp pine-barrens, Del. and southward.
15. P. cymòsa, Walt. Stem short, naked above, the numerous racemes in a usually nearly simple cyme, leaves narrow, acuminate; seeds globose, without caruncle.—Del. and southward.
Order 32. LEGUMINÒSÆ. (Pulse Family.)
Plants with papilionaceous or sometimes regular flowers, 10 (rarely 5 and sometimes many) monadelphous, diadelphous, or rarely distinct stamens, and a single simple free pistil, becoming a legume in fruit. Seeds mostly without albumen. Leaves alternate, with stipules, usually compound. One of the sepals inferior (i.e. next the bract); one of the petals superior (i.e. next the axis of the inflorescence).—A very large order (nearly free from noxious qualities), of which the principal representatives in northern temperate regions belong to the first of the three suborders it comprises.
Suborder I. Papilionaceæ. Calyx of 5 sepals, more or less united, often unequally so. Corolla inserted into the base of the calyx, of 5 irregular petals (or very rarely fewer), more or less distinctly papilionaceous, i.e. with the upper or odd petal (vexillum or standard) larger than the others and enclosing them in the bud, usually turned backward or spreading; the two lateral ones (wings) oblique and exterior to the two lower, which last are connivent and commonly more or less coherent by their anterior edges, forming the carina or keel, which usually encloses the stamens and pistil. Stamens 10, very rarely 5, inserted with the corolla, monadelphous, diadelphous (mostly with 9 united into a tube which is cleft on the upper side, and the tenth or upper one separate), or occasionally distinct. Ovary 1-celled, sometimes 2-celled by an intrusion of one of the sutures, or transversely 2–many-celled by cross-division into joints; style simple; ovules amphitropous, rarely anatropous. Cotyledons large, thick or thickish; radicle incurved.—Leaves simple or simply compound, the earliest ones in germination usually opposite, the rest alternate; leaflets almost always quite entire. Flowers perfect, solitary and axillary, or in spikes, racemes, or panicles.
I. Stamens (10) distinct.
[*] Leaves palmately 3-foliolate or simple; calyx 4–5-lobed; herbs. (Podalyrieæ.)
1. Baptisia. Pod inflated.
2. Thermopsis. Pod flat, linear.
[*][*] Leaves pinnate; calyx-teeth short. (Sophoreæ.)
3. Cladrastis. Flowers panicled, white. Pod flat. A tree.
4. Sophora. Flowers racemose, white. Pod terete, moniliform. Herbaceous.
II. Stamens monadelphous, or diadelphous (9 and 1, rarely 5 and 5); nearly distinct in n. 14.
[*] Anthers of two forms; stamens monadelphous; leaves digitate or simple; leaflets entire. (Genisteæ.)
5. Crotalaria. Calyx 5-lobed. Pod inflated. Leaves simple.
6. Genista. Calyx 2-lipped. Pod flat. Seed estrophiolate. Leaves simple. Shrubby.
7. Cytisus. Calyx 2-lipped. Pod flat. Seed strophiolate. Leaves 1–3-foliolate. Shrubby.
8. Lupinus. Calyx deeply 2-lipped. Pod flat. Leaves 7–11-foliolate.
[*][*] Anthers uniform (except in n. 13 and 29).
[+] Leaves digitately (rarely pinnately) 3-foliolate; leaflets denticulate or serrulate; stamens diadelphous, pods small, 1–few-seeded, often enclosed in the calyx or curved or coiled. (Trifolieæ.)
9. Trifolium. Flowers capitate. Pods membranaceous, 1–6-seeded. Petals adherent to the stamen-tube.
10. Melilotus. Flowers racemed. Pod coriaceous, wrinkled, 1–2-seeded.
11. Medicago. Flowers racemed or spiked. Pods curved or coiled, 1–few-seeded.
[+][+] Leaves unequally pinnate (or digitate in n. 13); pod not jointed; not twining nor climbing (except n. 20).
[++] Flowers umbellate (solitary in ours) on axillary peduncles. (Loteæ.)
12. Hosaekia. Leaves 1–3-foliolate. Peduncle leafy-bracteate. Pod linear.
[++][++] Flowers in spikes, racemes, or heads. (Galegeæ.)
[=] Herbage glandular-dotted; stamens mostly monadelphous; pod small, indehiscent, mostly 1-seeded; leaves pinnate (except in n. 13).
13. Psoralea. Corolla truly papilionaceous. Stamens 10, half of the anthers often smaller or less perfect. Leaves mostly palmately 3–5-foliolate.
14. Amorpha. Corolla of one petal! Stamens 10, monadelphous at base.
15. Dalea. Corolla imperfectly papilionaceous. Stamens 9 or 10; the cleft tube of filaments bearing 4 of the petals about its middle.
16. Petalostemon. Corolla scarcely at all papilionaceous. Stamens 5; the cleft tube of filaments bearing 4 of the petals on its summit.
[=][=] Herbage not glandular-dotted (except in n. 23); stamens mostly diadelphous; pod 2-valved, several-seeded; leaves pinnately