MIMOSACEAE 579 
oblique, small and in many pairs or large and in few pairs: flowers mostly perfect, sessile, 
in dense heads. Calyx 5-lobed. Corolla of 5 distinct petals. Stamens 10, exserted. 
Ovary stalked. Style filiform. Ovules numerous. Pods broadly linear, flat. Seeds 
crosswise in the pod. 
Leaves with 14-18 pairs of pinnae: branches tomentose: leaflets less than 1.5 mm. broad. 
1. L. pulverulenta. 
Leaves with 2-10 pairs of pinnae: branches glabrous or glabrate: leaflets over 1.5 mm. broad 
Leaflets 20-40, mostly thrice as long as broad : pods with membranous valves. 2. L. glauca. 
Leaflets 12-16, mostly less than twice as long as broad: pods with leathery valves. 3. L. retusa. 
1. Leucaena pulverulénta Benth. A small tree, sometimes 18 m. tall, with finely 
een inflorescence. Leaves 1-2 dm. long, with 28-36 pinnae ; leaflets 60-120, the 
lades narrowly oblong, acute: peduncles often clustered, 1-3.5 cm. long: heads globose, 
1-1.5 em. in diameter: calyx campanulate, 1-1.5 mm. high; lobes obtuse: petals linear- 
spatulate, about thrice as long as the calyx, pubescent near the tip: stamens hardly twice 
as long as the petals : pods linear, 10-20 cm. long. 
In rich &oil, southern Texas and Mexico. Spring. 
2. Leucaena glaüca (L.) Benth. A small tree, sometimes 10 m. tall, with spread- 
ing branches and tomentose twigs. Leaves 1-3 dm. long, with 6-20 pinnae ; leaflets 20-40, 
the blades narrowly oblong to lanceolate, oblique, 6-12 mm. long, acute : peduncles tomen- 
tose, 1-4 cm. long: heads globose, 1-3 cm. in diameter: calyx obconic, 1 mm. long, sub- 
tended by peltate bracts; lobes obtuse: petals linear-oblong or linear-spatulate, erect, 
more than twice as long as the calyx, pubescent: stamens nearly thrice as long as the 
petals: pods linear, 10-15 cm. long, acute or acuminate at both ends. 
In sandy or rocky soil, Florida to Texas and Mexico. A native of tropical America, now widely 
distributed in alltropicalregions. Spring. 
.,9. Leucaena retüsa Benth. A shrub, with tomentose twigs. Leaves 1-2 cm. long, 
with 4-10 pinnae; leaflets 12-16, the blades leathery, oblique, obovate or ovate to oval or 
oblong, 1-3 cm. long, prominently nerved, usually apiculate : peduncles 5-8 cm. long: 
heads globose, about 2 cm. in diameter: calyx obconic, 3-3.5 mm. long: pods linear, 
15-25 cm. long, acute or acuminate at both ends. 
On plains and prairies, southern Texas and New Mexico. Spring. 
9. ÁCUAN Medic. 
Perennial unarmed herbs or somewhat shrubby plants. Leaves with 2-pinnate blades : 
leaflets numerous. Flowers in peduncled greenish or whitish head-like spikes, perfect, or 
the lower ones staminate or neutral, and sometimes apetalous. Calyx 5-lobed. Corolla of 
5 distinct or slightly united petals. Stamens 5-10, exserted : filaments distinct or nearly 
so. Ovary nearly sessile. Ovules numerous. Pods very narrow or oblong, unarmed, 2- 
valved. Seeds lengthwise or oblique in the pod. [Desmanthus Willd.] 
Stamens 5. 
Pods 4-6 mm. wide, in compact heads: peduncles longer than the »* A darti rima 
ries og eg wide, in loose clusters : peduncles shorter than the s. 2. A. leptoloba. 
Leaves mostly with 8-12 pinnae. mesi 
Stems glabrous or nearly so: uncles 1-2 em. long. 9. A. Jani 
Stems velvety pubescent: peduncles 2.5-5 em. long. kim aseo 
Leaves mostly with 2-6 pinnae. 
Peduncles 1-2.5 em. long. 
Leaf-rachis and its branches glabrous: leaflets not ciliate. 5. A. depressa. 
-rachís and its branches pubescent : leaflets ciliate. 6. A. acuminata. 
Peduncles 4-12 em. long. 
Pinnae mostly with 12-18 leaflets : leaflets glaucous beneath, glabrous or nearly 
80: pods 3 mm. wide. 
Pinnae mostly with 20-28 leaflets: leaflets ciliate and pubescent beneath: 
pods 2 mm. wide. 8. A. fallax. 
1. Acuan Iliinoénsis (Michx.) Kuntze. Stems erect or ascending, 3-10 dm. tall, 
pea branched, glabrous or nearly so: leaves with 20-28 pinnae; leaflets numerous, 
i e blades linear-oblong, 2.5-3.5 mm. long, acute, not reticulated : peduncles 2.5-8 cm. 
ong, usually shorter than the subtending bracts : spikes less than 1 cm. in diameter : pods 
^s di numerous, 1.5-2 em. long, curved and slightly spirally twisted, in heads 2-3 em. 
m diameter. [Desmanthus brachylobus ( Willd.) Benth. ] 
PE soil, and on river banks, Minnesota to Tennessee, Florida, Colorado and Texas. Spring and 
2. Acuan leptóloba (T. & G.) Kuntze. Stems ascending, 3-10 dm. tall, sparingly 
branched, with scabrous AE ure with 10-20 pinnae ; yen Te numerous, the bladés 
-I 
. A. reticulata. 
