PAPILIONACEAE. 33 



sessile, linear or subulate; flowers piak or rose, in a dense terminal spike. 

 Sandy moist soil, July-August; infrequent; Fayette, Muscatine, Johnson, and 



Story counties. 



P. cruclata L. Annual: stem 4-10 inches high, square or slightly wing- 

 angled, with spreading branches: leaves mostly in 4's, linear or oblanceolate: 

 spikes sessile or nearly so: flowers purple, greenish, or white: wings triangu- 

 lar-ovate, slightly cordate, awn-pointed. In mossy shaded places: July-Sep- 

 tember: Lake township, .Muscatine county. 



P. verticillata L. Annual, glabrous: stems 4—12 inches high, branches 

 mostly opposite, spreading: leaves in whorls of 4 or .">, a few scattered, acute, 

 punctate, linear: spikes long-peduncled: flowers purplish or greenish: wings 

 broadly oval, clawed, shorter than the pod. Prairies and open woods: June- 

 September: common. 



PAPILIONACEAE L. Pea Family. 



Trees, shrubs, vines or herbs, with alternate compound, stipulate 

 leaves, and papilionaceous perfect flowers in spikes, heads, panicles or 

 racemes. Calyx of 3 sepals, often unequal, more or less united. Coral la 

 of 5 petals; the upper one known as the standard is the largest and in 

 the bud encloses the others, usually reflexed; the lateral petals or wings 

 ate oblique and exterior to the two lower petals; the lower more or less 

 conniving by their edges to form the keel which encloses the stamens and 

 pistil. Stamens monodelphous, diadelphous or distinct, 10, rarely 9 or 5. 

 Ovary simple, superior, usually 1-celled; style simple. Fruit a legume, 

 2-valved. 1-many seeded, dehiscent or indehiscent, or else a loment. This 

 and the following two families are usually included under Leuuminosae. 



Tribe Podalyrieae. Leaves 3-foliate; stamens distinct. 

 Baptisja. A single genus in our area. 



Tribe Genisteae. Leaves digitate or simple; stamens monodelphous: 

 anthers of 2 kinds. 



Crotalaria. Leaves simple: calyx nearly equally 5-lobed. 

 Lupincs. Leaves digitate: calyx deeply "2- lipped. 



Tribe Trifolieae. Leaves 3-foliate, leaflets denticulate: stamens diadel- 

 phous. 



Tkjfoltum. Flowers capitate ; pods straight. 



Memlotcs. Flowers racemose: pods coriaceous. 



Medicago. Flowers racemose or spicate : pods curved or coiled. 



Tribe Loteae. Leaves 3-foliate. leaflets entire: stamens diadelphous. 



Hosackia. With us the only genus. 

 Tribe Psoraleae. Leaves glandular-dotted: stamens mostly monodel- 

 phous: pod small, indehiscent. 



; a i. la. Leaves digitately 3 -5 -foliate. 

 A.mokpha. Coralla of one petal, the standard. 



DiLLA. Wings and keel adnate to the middle of the cleft stamen tube. 

 Pltalostemox. Corolla nearly regular; stamens 5. 



Tribe Galegeae. Leaves usually not dotted, pinnately several-foliate: 

 flowers racemose; stamens mostly diadelphous. 

 Tephrosu. Herb: leaves odd-pinnate : pod flat. 

 Kobinu. A small tree: leaves odd-pinnate 



. ■ LUIS. Pod inflated, partly or entirely 2-celled. 

 OXYTBOP1& Stemless silky-pubescent herbs; keel pointed. 

 <;lv< vkkhi/.a. Leave- scaly or dotted: pod covered with hooked prickle-. 



