188 



FABACEAE. 



petals and stamens. Petals commonly 5 and irregular; 

 the standard superior, larger and external, covering in the 

 bud the 2 lateral ones (wings), these covering the 2 infer- 

 ior pair which are more or less united above, forming the 

 keel. Stamens and pistils enclosed in the keel. Fila- 

 ments 10, 9 commonly united below into a sheath about 

 the pistil and 1 distinct (diadelphous) , or all united 

 {monadelphous) , or distinct; anthers 2-celled, dehiscent 

 longitudinally. Pistil simple, free, becoming a legume 

 in fruit; ovules few or many on the single parietal pla- 

 centa; style usually incurved. Legume 1-celled, 2- 

 valved, sometimes falsely 2-celled by the intrusion of the 

 placenta. Endosperm usually wanting. (Leguminosae.) 



1. XYLOTHERMIA Greene. 



A rigid much branched spinescent shrub with small 

 nearly sessile 1-3-foliate exstipulate leaves and large 

 solitary subsessile purple flowers. Calyx campanulate, 

 repandly 4-toothed. Petals equal; standard orbicular, 



