70 
oblong to nearly orbicular, sometimes emarginate at each end, 8 to 
6 lines long, 2 to 5 lines broad, v*dth wings broader than body 
(also extending below body), and prominent dorsal and intermed- 
iate ribs: oil-tubes large and solitary in the intervals, 2 on the com- 
missural side: seed-face slightly concave. (Fig. 64.) — P. triterna- 
tum^ var. ■platycarpum Ton*. Stansb. Rep. 389. 
From Arizona and California (iif K. Curran) to Washington Terr itory, 
Idaho, and Montana. 
In determining this species it is important to remember that wings 
develops last, and hence very mature fruit must be obtained to show wings 
of full width. 
34. P. triternatum Nutt. Ton*. & Gray, FI. i. 626. Cau- 
lescent or acaulescent, puberuleirt, 1 to 2^4 feet high: leaves biter- 
nate to triternate; leaflets from narrowly linear to linear-lanceolate, 
2 to 4 inches long: umbel unequally 5 to 18-rayed, with invol- 
ucels of lanceolate or setaceous bractlets; i*ays ^ to 2^ inches 
long; pedicels a line or more long: fruit narrowly oblong, 
glabrous (rarely pubescent), 3 to 6 lines long, to 2 lines 
broad, with narrow wings, and somewhat prominent dorsal and 
intermediate ribs: oil-tubes very large and broad, solitary in the 
intervals, 2 on the commissural side: seed-face very slightly con- 
cave. (Fig. 65.) — Inch P. triternatum^ var. leftocar^um Nutt. 
From California to Washington Territory, Idaho, and British Columbia 
{Macoun). FI. April to June. 
One of the most abundant and variable of our species. It shades off 
towards P. siuiplex sometimes in a most perplexing way. The following 
are extreme forms: 
Var. macrocarpum. A more robust form, with broader 
leaflets, longer rays, and larger fruit (6 to 8 lines long). 
Oregon {Suksdorf 502), Dalles {Kellogg, in 1869), Hood Eiver {Hender- 
son 390). 
Var. brevifolium. Stouter and more rough puberulent, with 
more compact leaves, having stout inflated petioles, and shorter 
and broader often toothed leaflets. 
Oregon, Klickitat county {Howell 379, in 1881), and rocky hillsides near 
the Dalles {Suksdorf). 
Var. alatum. Leaves with very narrowly linear and elon- 
gated segments; fruit 5 to 6 lines long, with broader wings (some- 
times as broad as body or even broader), but the elongated form is 
that of P. triternatum and not P. simplex. 
