UMBELLIFERAE. 263 



tened dorsally; stylopodium flattened; dorsal ribs filiform, the 

 lateral extended into broad wings; oil-tubes small, solitary in 

 in the intervals, 2-4 on the commissural side. 



Pastinaca sativa L. Glabrous; stems 60-90 cm. high; leaves pinnately 

 compound, the leaflets ovate to oblong, incisely serrate; flowers yellow; fruit 

 oval. 



The common parsnip of the garden frequently becomes wild. 



348. LEPTOTAENIA. 



Usually tall or stout, glabrous, nearly acaulescent; roots thick, 

 fusiform, often very large; leaves usually large, pinnately de- 

 compound; involucre of few bracts or none; involucels of numer- 

 ous small bractlets; flowers yellow or purple; calyx- teeth obsolete 

 or sometimes evident; stypolodium wanting; fruit flattened 

 dorsally, oblong-elliptical, glabrous; carpel with dorsal and inter- 

 mediate ribs filiform or obscure; lateral wings very thick and 

 corky; commissural face with a prominent central longitudinal 

 ridge left after separation from the carpophore; oil-tubes 3-6 

 in the intervals, 4-6 on the commissural side, mostly small, some- 

 times obsolete ; seeds very flat, with plane or slightly concave face. 



Leptotaenia dissecta Nutt. Nearly glabrous and somewhat glaucous; 

 stems stout, 30-90 cm. high; leaves mostly basal, large, ternate then thrice 

 pinnate; ultimate segments ovate to oblong, incisely pinnatifid, puberulent 

 on the veins beneath, 1-2.5 cm. long; peduncle elongated; umbel 8-20-rayed; 

 bracts linear; flowers brownish-purple; fruits 10-18 mm. long. 



Vancouver Island, British Columbia to California, first collected by Nuttall 

 near the mouth of the Willamette River. 



349. HYDROCOTYLE. 



Low perennial herbs growing in or near water, with slender 

 creeping stems; leaves orbicular-peltate or reniform; flowers 

 small, white, in simple or proliferous umbels without an involucre; 

 calyx teeth minute or obsolete; fruit more or less orbicular, 

 strongly compressed laterally; carpel with 5 primary ribs, the 

 dorsal marginal, broad or filiform; intermediate ribs filiform, 

 usually curved; lateral ribs filiform or broad; oil-bearing layer 

 prominent beneath the epidermis, occasionally with small tubes. 



Hydrocotyle ranunculoides L.f. Floating or creeping in mud; leaves 

 round-reniform, thick, crenately 3-7-cleft; peduncles 37 cm. long, shorter 

 than the petioles, reflexed in fruit; umbel 5-10-flowered; fruit 2-3 mm. broad. 



Ponds and muddy banks, not rare. 



350. CICUTA. WATER HEMLOCK. 



Smooth poisonous marsh perennials; leaves pinnately com- 

 pound; leaflets serrate; involucre of few bracts or none; in- 

 volucels of several slender bractlets; flowers white; calyx-teeth 

 rather prominent; stylopodium low, sometimes low-conical; 



