18i S. Kurz — Contrih lit ions toimrds a [No. 2, 



Shrubby annual ; leaves small, sessile with, broad base and almost half-stem-clasping ; 

 involucre-bracts narrowed into filiform tails ; peduncles almost glabrous, 



. . B. amplectens. 



Low perennial, branched and ascending from the base, thinly pubescent ; peduncles 



spreadingly pubescent ; involucre-bracts very acute ; leaves rather large, sessile 



with a rounded base, B. bifoliata. 



X X Flower-heads in panicles, racemes, or rarely densely packed into 

 shorter or lorger spikes. 

 + Serratures or teeth of the leaves spiny indurated at their tips. 

 Spreading perennial, branched from the base and procumbent, sparingly pilose ; leaves 

 small, the serratures few and coarse ; flower-heads few, forming irregular depau- 

 perate panicles, B. oxyodonta. 



Erect, simple or branched annual, more or less appressed silky-pilose ; leaves rather 

 large, doubled-spiny-serrulate ; flower-heads in regular panicles, . , . .B. spinellosa. 

 + + Serratures or teeth of the leaves various, but never spiny- 

 indurated. 

 t Herbs, or biennials, simple or branched from the base, and 

 more or less villous, pubescent, or viscid-pub erulous, rarely 

 almost glabrous. 



O Flower-heads irregularly disposed and more or less pe- 

 duncled, forming panicles or rarely the panicle con- 

 tracted. 

 A Receptacle glabrous. 



X Florets blue to violet, rarely bluish white. 

 Tall herb, reduced and small, more or less viscid-pubescent ; leaves simple and petioled ; 

 flower-heads only 2 lin. long, on shorter or longer filiform peduncles, forming lax 



panicles, B. Wiglitiana. 



X X Florets all yellow. Flower-heads in lax pani- 

 cles. Peduncles slender, although sometimes 

 very short. Annuals, rarely becoming bien- 

 nials. 

 Erect, branched from the base, more or less silky-villous, but not viscid, the cauline 

 leaves simple and sessile or nearly so ; flower-heads 3 — 3| lin. long, in panicles 



sometimes pretty contracted but elongate, B. lacera. 



Erect, branchy, thinly viscid-pubescent, the cauline leaves simple and petioled ; flower- 

 heads about 4 lin. long, on long slender glandular peduncles, forming lax panicles, 



. . B. glandulosa. 



Erect, branchy, thinly puberulous, the cauline leaves (except in starved states) almost 



runcinate and petioled ; flower-heads about 3 lin. long with the involucral-bracts 



green and glabrous, on spreading stifi" capillary glabrous or glandular peduncles, 



in lax panicles, , B. diffusa. 



Erect, simple or branched, almost glabrous or usually more or less hirsute, the cauline 

 leaves (especially the lower ones) more or less runcinate ; flower-heads nearly 4 

 lin. long, with the involucral-bracts and the long slender peduncles pubescent, 



in lax panicles, B. lactuccefoUa. 



A A Receptacle hairy. Peduncles slender. 

 Branched or simple annual, shortly or rarely glandular-pubescent, the cauline leaves 

 usually runcinate ; flower-heads about 3| lin. long, longer or shorter peduncled, 

 forming lax leafless panicles, B, laciniata. 



