452 AMYGDALACEAE 



mm. long; fruit globose, 8-10 mm. in diameter, purplish or red. Ceraaus demissa 

 Nutt. River banks: B.C. — Ida. — Calif.; apparently also Black Hills of S. D., 

 but there a mere low shrub (f. Rydbergii Koehne) . Submont. My-Je. 



12. P. melanocarpa (A. Nels.) Rydb. Tree or shrub up to 10 m. high; 

 twigs reddish brown, glabrous; leaves obovate or oval, abruptly acuminate at 

 the apex, mostly rounded at the base, rather firm, paler beneath, glabrous on 

 both sides; peduncles slender, glabrous or rarely minutely puberulent, many- 

 flowered; petals about 6 mm. long; fruit dark purple or black, 6-8 mm. thick, 

 sweet, slightly astringent, shorter than the pedicels. Cerasus demissa melano- 

 carpa A. Nels. Hills and river banks: Alta. — N.D. — Kans. — N.M. — Calif. 

 — B.C. Plain — Submont. My-Je. 



2. EMPLECTOCLADUS Torr. Wild Almonds. 



Low shrubs, with divaricate, spinescent branches. Leaves fasciculate on 

 short branchlets, entire. Flowers 1-3, in axillary umbels, perfect. Hypanthium 

 campanulate, hairy within. Sepals and petals 5, imbricate. Stamens 10-15; 

 filaments slender, distinct. Drupe pubescent, with rather dry exocarp, which 

 splits on one side. Stone bony, flattened. 



1. E. fasciculatus Torr. A shrub 0.5-1 m. high, with divaricate branches, 

 more or less spinescent ; leaves fascicled on short branchlets, spatulate, nearly sessile, 

 5-10 mm. long, finely puberulent or glabrate; flowers sessile or nearly so; petals 

 linear-oblanceolate, white, 3 mm. long; stamens 10-15; fruit subglobose, pubes- 

 cent, about 1 cm. long. Prunus fasciculata A. Gray. Amygdalus fasciculatus 

 Greene. Desert regions: Calif. — s Utah — Ariz. L. Son. Mr-Ap. 



Family 63. MIMOSACEAE. Mimosa Family. . 



Herbs, shrubs, or trees, usually with twice or thrice pinnately compound 



leaves, with stipules, the latter often modified into spines. Flowers mostly 



perfect, regular, in heads or spikes. Sepals 3-6, partly united, valvate. 



Petals as many, valvate, distinct or partly united. Stamens of the same 



number, twice as many, or numerous. Pistil solitary, in fruit becoming a 



legume. 



Legiimes flat; valves not separating from the continuous margins. 1. Acuan. 



Legumes 4-angIed; valves separating from tlie continuous margins. 2. Morongla.. 



1. ACUAN Medic. Prairie Mimosa. 



Perennial unarmed herbs, rarely somewhat shrubby. Leaves bipinnate, with 

 numerous leaflets. Flowers in peduncled heads or head-like spikes, perfect or 

 the lower ones staminate, sometimes without petals. Calyx 5-lobed. Petals 

 5, distinct, or slightly united at the base. Stamens 5 or 10, exserted; filaments 

 distinct or nearly so. Ovules numerous. Pod elongate, unarmed. [Desmanthus 

 Wiild.] 



1. A. illinoensis (Michx.) Kuntze. Erect or ascending herb, 3-10 dm. 

 high, glabrous or nearly so; leaves bipinnate, with 20-30 pinnae; leaflets numer- 

 ous, linear-oblong, 2.5-3.5 mm. long; peduncles 2.5-8 cm. long, longer than the 

 pods; stamens 5; pods 4-6 mm. wide, in compact heads, slightly spirally twisted. 

 Desmanthus brachylobus (Willd.) Benth. River banks: Tenn. — Fla. — Tex. — 

 N.M.— S.D. Plain. My-Je. 



2. MORONGIA Britton. Sensitive Brier. 



Perennial herbs or slirubs, with spreading prickly stems. Leaves bipinnate, 

 usually sensitive; leaflets numerous, usually small. Flowers perfect or polyga- 

 mous, in axillary peduncled heads. Calyx 4- or 5-lobed. Petals 4 or 5, united 

 to about the middle. Stamens 8-10, exserted; filaments distinct or nearly so. 

 Ovules numerous. Pod narrow, 4-angled, prickly all over, finally 4-valved, the 

 valves separating from the margins. [Schrankia Willd., not Medic] 



