MIMOSACEAE 575 



2. Laurocerasus Caroliniana (Mill.) Roem. An evergreen tree, sometimes 12 m. 

 tall, with a slender trunk rarely over 3 decimeters thick. Leaf-blades leathery, narrowly 

 elliptic to oblono^-lanceolate, sometimes remotely toothed, acuminate at both ends or acute 

 at the base, slightly revolute, lustrous above, dull beneath ; petioles 5-8 mm. long : ra- 

 cemes shorter than the leaves, rather dense : pedicels club-shaped, 2-4 mm. long, subtended 

 by early deciduous scarious acute bracts : sepals suborbicular, reflexed, deciduous : petals 

 boat-shaped, fully 1 mm. long, erect, smaller then the sepals : drupes oblong or oval, 10- 

 13 mm. long, abruptly pointed, black, lustrous : stone ovoid. 



In river valleys and near the coast, North Carolina to Florida and Texas. Winter and spring, 

 fruit persistent for a year. 



Family 15. MIMOSACEAE Eeicheub. Mimosa Family. 



Herbs, shrubs or trees, with erect or prostrate stems. Leaves alternate : 

 blades usually compoimd, commonly 2-3-pinnate : stipules various, sometimes 

 spine-like. Flowers mostly perfect, sometimes polygamous, relatively small. 

 Calyx of 3-6 valvate partially united sepals. Corolla regular, of 3-6 distinct or 

 partially united valvate petals. Audroecium of as many stamens as there are 

 petals or twice as many, or numerous, usually conspicuously exserted. Fila- 

 ments distinct or monadelphous. Gynoecium of a single carpel. Ovary supe- 

 rior, 1-celled. Style simple. Ovules several or numerous. Fruit a legume (pod). 

 Seeds with thick cotyledons. Endosperm wanting. 



Stamens numerous, more than 10. 



Filaments partially united into a tube. 



Valves of the pod not separating from the continuous margin. 

 Pods with woody or thick-leathery valves. 



Leaves with 4 leaflets, or if more, few and relatively large : spikes 

 head-like : ovary stipitate : pods contorted, with" thick-leathery 



valves. 1. PiTHECOI.OBIUM. 



Leaves with many relatively small leaflets : spikes elongated : ovary 



sessile : pods straight or merely curved, with woody valves, 2. Sidekocarpos. 



Pods with membranous or thin-leathery very flat valves. » 



Ovary stipitate : calyx very short and different from the corolla in 



texture. 3. Havardia. 



Ovary sessile : calyx simulating the corolla, but much shorter, and 



quite similar in texture. 4. Albizzia. 



Valves of the pod separating from the continuous margin. 5. Lysiloma, 



Filaments distinct, or the inner ones sometimes slightly united at the base. 

 Ovary stipitate : petals distinct or united, commonly only to below the mid- 

 dle : pods flat, dry. the seeds not in two distinct rows. 6. Acacia. 

 Ovary sessile : petals united into a tubular-funnelform, shallowly lobed co- 

 rolla : pods nearly terete or broader than high, pulpy within, ttie seeds 

 in two separate rows. 7. Vachellia. 

 Stamens as many as the petals or the corolla-lobes or twice as many. 

 Anthers without glandular appendages at the top. 



Valves of the pod not separating from the continuous margin. 



Shrubs or trees : seeds transverse in the pod. 8. Leucaena. 



Herbs : seeds lengthwise or oblique in the pod. 9. Acuan. 



Valves of the pod separating from the continuous margin. 



Pods slightly, if at all, flattened, 4-angled or with a broad margin, beaked, 



not jointed. 10. Morongia. 



Pods flat, jointed, not beaked. 11. Mimosa. 



Anthers, at least in the bud, topped by glandular appendages. 



Herbs : pods flat and thin, twice or thrice longer than broad. 12. Neptunia. 



Shrubs or trees : pods relatively thick, many times longer than broad. 

 Pods straight or merely curved, somewhat constricted between the seeds, 



in lax clusters. 13. Prosopis. 



Pods tightly coiled into a spiral, in bunch-like clusters. 14. Strombocarpa. 



1. PITHECOLOBIUM Mart. 



Shrubs or trees, usually armed. Leaves with 2-pinnate blades : leaflets few, often 4. 

 Flowers perfect or rarely polygamous, in head-like spikes. Calyx 5-6-lobed. Corolla of 

 5-6 partially united petals. Stamens numerous, long-exserted : filaments often well united. 

 Ovary short-stalked. Ovules several or numerous. Pods narrow, contorted, often with 

 mealy or pulpy partitions within, 2-valved, but not elastically so, sometimes tardily so. 

 Seeds partially enclosed in highly colored arils. The plants often flower throughout the 

 year. Catsclaw. 



Leaflets with leathery blades : petioles shorter than the petiolules : ovary pubescent. 1. P. Guadalupense. 

 Leaflets with membranous blades : petioles longer than the petiolules : ovary glabrous. 



2. P. Unguis-Caii. 



