114 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
gated (5 to 13 cm. long); uppermost leaves simple; umbel 9 to 12- 
rayed, with prominent involucre, and involucels of numerous scari- 
ous lanceolate long-acuminate bractlets 6 mm, long; rays 5 cm. long; 
pedicels 16 to 20 mm. long; fruit linear-oblong, 8 mm. long, 3 mm. 
broad; oil tubes large, solitary in the intervals, 4 on the commissural 
side; sulcus of seed face deeper than in other species, and with more 
prominent central ridge. 
Type locality, ‘‘ wet ravines, Knights Ferry, Stanislaus County,” 
California; collected by Bigelow, May 8, 1854; type in Herb. Gray. 
Central California. 
Specimens examined: 
CatiForNIA: Mendocino County, G. R. Vasey, in 1875; Santa Lucia Mountains, 
G. R. Vasey 227, July, 1880; Greene. 
33. SIUM LL. Sp. Pl. 1: 251. 1753. 
Calyx teeth minute. Fruit flattened laterally, ovate to oblong, 
glabrous. Carpel with prominent corky nearly equal ribs, each with 
a prominent group of strengthening cells at tip. Stylopodium de- 
pressed; styles short. Oil tubes 1 to 
3 in the intervals (never solitary in all 
the intervals), 2 to 6 on the commis- 
sural side. Seed subangular, with 
5 plane face. 
Smooth perennials growing in water 
f or wet places, with pinnate leaves 
MiG. SE-—Sham cleutaefolium: ab < 2 and serrate or pinnatitid leaflets, in- 
volucre and involucels of numerous narrow bracts, and white flowers. 
First species cited, Stum latifolium L. 
A genus of about 10 species, belonging to the north temperate 
regions of both hemispheres, and also in South Africa. 
Stout and tall; leaflets narrow; fruit larger (3 mm. long) ........ 1. WS. cicutaefolium, 
Weak and lower; submerged or floating leaves broad; yt smaller (2 mm. long). 
Se } fh B eo" OP /787 2. S. carsonii. 
1. Sium cicutaefolium Gmelin, Syst. 2: 482. * 1791, Fic. 31. 
Sium lineare Michx. Fl. Bor. Am. 1: 167, 1803. 
Stout, 6 to 8 dm. high; leaflets 3 to 8 pairs, linear to lanceolate, 
sharply serrate and mostly acuminate, 5 to 13 em. long (lower leaves 
sometimes submersed and finely dissected, as in the next); umbel 
many-rayed; rays 2.5 to 4m. long; pedicels 2 to 6 mm. long; fruit 
3mm. long, with prominent ribs; oil tubes 2 to 6 on the commissural 
side. 
Type locality unknown to us. 
In swamps from Newfoundland to Virginia, west to British Colum- 
bia and northern California. We have no specimens from the southern 
belt of the United States. 
