146 LEGUMINOSAE. 
CytTisus. Broom. 
(Family Leguminosae). 
Shrubs, usually rather small: 
commonly deciduous. Twigs slen- 
der, terete or more usually ribbed 
or grooved: pith small, roundish, 
continuous. Buds small, solitary, 
sessile, round-ovoid, with about 4 
often indistinct scales. Leaf-scars 
alternate, elevated, minute: bun- 
dle-trace 1, indistinct: stipules or 
minute stipule-scars at top of the 
leaf-cushion. Oytisus scoparius is 
frequently referred to as Spar- 
tium; and Laburnum, as Cytisus. 
1. Twigs forming blunt slender 
spines. (1). C. pungens. 
Not at all spiny. 2. 
2. Twigs distinctly ridged or 
angular, never villous. 3. 
Twigs obscurely ridged, staring- 
pubescent. (2). C. nigricans. 
Twigs terete. 6. 
3. Twigs narrowly ridged. (3). C. canariensis. 
Twigs prominently angled or ridged. 4. 
4. Twigs finely granular, almost winged. (4). C. scoparius. 
Twigs not granular. 5. 
5. Twigs glabrescent or appressed-pubescent. 
(5). C. glabrescens. 
Twigs quite glabrous. C. purpureus. 
6. Pubescence rather short and appressed. C. leucanthus. 
Pubescence long and loose. 7. 
7. Erect. C. hirsutus. © 
Low and spreading. C. supinus. 
References on p. 148. 
