178 UMBELLIFERAE. 



attenuation at the base; oil-tubes obsolete in the mature fruit 

 (often numerous in young fruit) ; seed face from slightly concave 

 to deeply sulcate. 



Fruit glabrous. 0. occidentalis. 

 Fruit with bristly ribs. 



Foliage glabrous or nearly so. O. divaricata. 



Foliage strigose-pubescent. O. brevipes. 



Osmorhiza occidentalis Torr. Stout, more or less puberulent, 40-80 cm. 

 tall; leaves 2-3-ternate; leaflets ovate-oblong, acute, serrate, 4-10 cm. long; 

 umbel 5-12-rayed; involucels few or none; fruit 12-16 mm. long, obtuse at 

 base, glabrous, shining, beaked, the ribs prominent and sharp. On moist 

 slopes in the mountains. 



Osmorhiza divaricata (Britt.) Nutt. Glabrous or nearly so, 30-60 cm. 

 tall; leaves biternate; leaflets ovate or lanceolate, acute or acuminate, thin, 

 coarsely serrate and more or less incised; umbels 2-9-rayed; pedicels mostly 

 1-2 cm. long; involucels none; fruit 16-20 mm. long, bristly-hairy on the ribs, 

 the carpels distinctly beaked, much narrowed at the base. In woods. 



Osmorhiza brevipes (Coult. & Rose) Suksdorf. (Washinglonia brevipes 

 Coult. & Rose.) Similar to O. divaricata but pubescent with white hairs; 

 pedicels shorter, 4-12 mm. long, decidedly shorter than the fruit, which is 

 14-16 mm. long. In open woods, Blue Mountains. 



255. CAUCALIS. 



Mostly hispid annuals; leaves pinnately dissected, with very 

 small segments; flowers white; calyx-teeth prominent; fruit 

 short, ovate or oblong, flattened laterally; carpel with 5 filiform 

 primary ribs with spreading bristles and 4 prominently winged 

 secondary ones with barbed or hooked prickles; stylopodium 

 thick, conical; oil-tubes solitary in the intervals. 



Caucalis microcarpa H. & A. Annual, erect, branched, 8-20 cm. tall, 

 more or less hairy; leaves pinnately much dissected, the ultimate segments 

 linear-oblong, 2.5 mm. long; umbels unequally 3-6-rayed; involucral bracts 

 resembling the leaves; involucels usually entire; fruit oblong, armed with rows 

 of hooked prickles. Sandy soil, in the warmer valleys. 



256. HERACLEUM. 



Tall stout perennials; leaves large, ternately compound; in- 

 volucres deciduous; involucels of numerous bractlets; flowers 

 white, in large many-rayed umbels; calyx-teeth small or obsolete; 

 petals obcordate, the outer ones often dilated and 2-cleft; stylo- 

 podium thick, conical ; fruit broadly ovate, very much flattened 

 dorsally, somewhat pubescent; carpel with dorsal and inter- 

 mediate ribs filiform ; the broad lateral wings contiguous to those 

 of the other carpel, strongly nerved toward the outer margin; 

 oil-tubes solitary in the intervals, conspicuous, about half as long 

 as the carpel, 2-4 on the commissural side; seed very much 

 flattened dorsally. 



