UMBELLIFER^. . 151 



7. SIUM, Diosc. (WATER PARSNIP). Glabrous perennial aquatics, 

 with angled stems, pinnate leaves with leaflets pinnatifid or serrate, and 

 white flowers; the involucres and involucels of several bracts. Calyx- 

 teeth minute. Fruit oblong, ovate or nearly globose; ribs prominent or 

 obscure; oil-tubes few or many in the intervals. 



* Fruit with corky ribs; oil-tubes between them. 



L 8. heterophyllum, Greene. Stem stoutish and brittle, strongly 

 angular and somewhat flexuous, 3 ft. high, from a cluster of fleshy fibrous 

 roots, these thickened below the middle: lowest leaves simple, 210 in. 

 long, rhombic-lanceolate, serrate or laciniate, on a stout fistulous petiole 

 which is still longer and usually submerged; the later radical 3-lobed or 

 -parted, thus passing to the cauline which are pinnate, mostly with only 

 2 or 3 pairs of leaflets, these broadly lanceolate, acute, serrate: bracts of 

 involucre broadly lanceolate, acute at each end: fr. 1J lines long, broadly 

 ovoid; oil-tubes broad, solitary between the ribs, 2 on the face: seed 

 angular. Common in brackish swamps, under the influence of tide- 

 water, at Suisun, Stockton, etc. 



* * Fruit with angled corky covering; oil-tubes beneath this. 



2. S. erectum, Huds. Stems angular, 13 ft. high, from a stolon- 

 iferous crown, usually erect, corymbosely branching above: leaflets 

 about 6 pairs, ovate oblong to linear, 1J 2 in. long, often laciniate at 

 base, the upper ones usually more or less deeply incised: peduncles 1 2 

 in. long: rays 1 in. or less: involucre and involucels of 6 8 linear entire 

 lanceolate bracts: fr. % line long, less compressed than in the above: 

 oil-tubes small in twos and threes, concealed beneath the corky covering 

 (confluent ribs). San Mateo Co. 



8. CICUTA, Sealer. (WATER HEMLOCK). Glabrous tall branching 

 perennials of marshes and stream banks. Bootstocks short and erect, or 

 horizontal and rooting from beneath. Leaves pinnately or ternately 

 compound. Umbels of white flowers many-rayed; involucre small or 0; 

 involucels of several small bractlets. Calyx-teeth small, acute. Stylo- 

 podium depressed. Fruit broadly ovate or rounded, slightly compressed 

 laterally, but the commissure narrow; ribs broad, obtuse, corky; oil- tubes 

 solitary in the intervals. Seed subterete. 



1. C. Bolanderi, Wats. Roots numerous, very coarse, 47 in. long, 

 whorled around the base of a short-conical strictly erect axis: stem stout, 

 erect, 49 ft. high, purplish below and very glaucous, paniculate from 

 below the middle: radical leaves on petioles 2 ft. long or more, the blade 

 twice or thrice pinnate: leaflets narrowly lanceolate-acuminate, 2 4 in. 

 long, closely and sharply serrate, the setaceous tips of the teeth some- 

 what spreading. Marshes about Suisun Bay; also in similar situations 

 (always within reach of tide-water) near Napa. 



