59 
(/or/ olO), Idaho {Wilcox), Yellowstone Falls {Parry liy), and Montana 
{Watson, Canby 151), northward into British Columbia. FI. May to July. 
This species is extremeiy variable in foliage, and hence hard to define 
clearly in this regard. Collectors seem to have contused it with P. triter- 
natum, but its tuberous roots and glabrous character, as well as its much 
narrower fruit-wings, should serve as distinguishing characters. 
P. Icevigaftim has also been mistaken for P. ambiguum, but its broader 
fruit-wings and. much reduced leafiets should easily separate them. 
^ Var. leptocarpum. Fruit sessile or nearly so, making a 
close somewhat divaricate cluster: rays few and very unequal. — 
triternatuni^ var. leptocarpum Ton*. & Gray, FI. i. 626. 
Oregon {Nuttall, Geyer 557, Howell 417, Gusick .359). 
8. P. circumdatum Watson, Proc. Am. Acad. xxii. 474. 
Stems solitary from a deep-seated constricted tuber, glabrous or 
puberulent, foot or less high: leaves ternate-quinate, the segments 
once or twice pinnatisect, lobes linear, 1 to 8 or 4 lines long: umbel 
unequally 6 to 12-rayed, with involucels of conspicuous broadly 
oblanceolate (often united) bractlets, becoming scarious; rays to 
inches long; pedicels very short: fruit oblong-elliptical, gla- 
brous, 3 or 4 lines long, lines broad, with narrow wings, and 
very prominent dorsal and intermediate ribs: oil-tubes 4 on the 
commissural side: seed-face concave, with a prominent central 
ridge. (Fig. 45.) 
Abundant on hillsides in Oregon, the Dalles {Nevius), John Day Val- 
iev {Howell}, Wallowa, region {Gusick), Blue Mountains {Henderson)', Mon- 
tana, near Bozeman {Scribner 66 a), Little Belt Mts. {Scribner 66), Belt 
River Canon {Williams 149), Bozeman Pass and Little Blackfoot River 
{Ganby 152); Yellowstone Park {Tweedy 854); N. W. Wyoming {Parry 120); 
Dakota (Mess Eloise Pwt/er), Little Missouri (Ganby 152 a). FI. May to 
August. 
§ 2. Stout, glabrous only in P. Qrayi, from large roots (in P. macro- 
carpum and P. eur year pum owding in an oblong sometimes large tuber): 
leaves mostly large and very finely dissected, the ultimate segments fili- 
form or narrowly linear: fm"*' wings broader (from half as broad as body to 
somewhat broader than body): oil-tubes 1 to 3 in the intervals (solitary in 
two species). 
* Flowers yellow : fruit glabrous : acaulescerit plants. 
9. P. foeniculaceum Nutt. Ton*. & Gray, FI. i. 627. Tomen- 
tose or glabrous, v^dth peduncles 8 to 12 inches long: leaves finely 
dissected, ternate-pinnate, with short filiform segments: umbel 
rather equally 3 to 12-rayed, with gamophyllous involucels, 5 to 
7-cleft and with conspicuously hairy margins; rays 1 to 2/^ inches 
