164 NATURAL HISTORY OF PLANTS. 



caducous (Hot regions of America, Mexico, southern Africa). 

 See p. 77. 



5. Cercidium Tul. — Flowers of Casalpinia; sepals subequal, 

 valvate or subimbricate with obliquely-cut margins. Stamens 10 ; 

 filaments pilose at base ; anthers uniform ovate versatile. Gerrnen 

 shortly stipitate, ao -ovulate ; style involute, apex acute; stigma 

 small terminal. Legume linear-oblong piano-compressed, mem- 

 branous or subcoriaceous, 2-valved ; sutures nerviform ; valves venu- 

 lose. Seeds ovate compressed albuminous. — Trees or shrubs ; 

 branches usually tortuous ; axillary twigs spinescent ; leaves small 

 2-pinnate ; leaflets small paucijugate ; flowers fascicled in short lax 

 racemes at defoliated nodes of wood ; bracts small membranous ; 

 bractlets small or (Central America, Mexico). See p. 77. 



6. Mezoneuruin Desf. — Flowers of Casalpinia; receptacle cupuli- 

 form or obliquely cymbiform, glandular within, sometimes subrostrate 

 posteriorly. Sepals 5, unequal (lowest sepal usually much the 

 largest) free, finally spreading or coalescing into a rather long 

 tube, much imbricated. Petals of Casalpinia ; highest petal 

 innermost, usually unlike the others, sometimes having within 

 above the base a small unequally-corrugated laciniate appendix. 

 Stamens 10; filaments glabrous or pilose at base. Germen 2-oc- 

 ovulate ; style usually clavate at apex ; stigma terminal small, 

 usually concave minutely ciliate. Legume piano-compressed, 

 membranous or coriaceous, longitudinally winged at superior suture, 

 indehiscent or sub- 2-valved. Seeds transverse piano-compressed, 

 orbicular or reniform ; embryo exalbuininous ; cotyledons flat ; 

 radicle short straight. — Trees or more frequently high climbing 

 shrubs, often prickly ; leaves 2-pinnate ; stipules small or ; flowers 

 in axillary simple or terminal compound racemes ; bracts usually 

 caducous ; bractlets (Tropical Asia, Africa, and Australia). 

 See p. 78. 



7. Hsematoxylon L. — Flowers subregular ; receptacle cupuli- 

 form subhemispherical, glandular within. Sepals 5, subequal, much 

 imbricated. Petals 5, oblong spreading subequal imbricated. Stamens 

 10, perigynous uniform; 5 oppositipetalous shorter. Germen 

 inserted in bottom of receptacle, free, shortly stipitate, pauci- 



