60 
long; pedicels 3 to 5 lines long: fruit broadly oblong, 2^ to 3 lines 
long, 2 lines broad, with wings half as broad as body, and promi- 
nent dorsal and intermediate ribs: oil-tubes 1 to 3 in the intervals, 
2 to 4 on the commissural side. 
From the Saskatchewan to Nebraska, Missouri (Tracy), Kansas (Oys- 
ter), Indian Territory and Texas (Reverchon). FI. March and April. 
The forms distributed under this name from New Mexico and Arizona 
are mostly P. villosum. 
10. P. Grayi C. & R. Bot. Gazette, xiii. 209. Glabrous, 
wdth peduncles 12 to 18 inches long: leaves ternate-pinnately de- 
compound, the ultimate segments linear, elongated or short, cus- 
pidate, very numerous: umbel rather equally 6 to IB-rajmd, with 
involucels of distinct linear-subvdate bractlets; rays 1 to 3 inches 
long; pedicels 5 to 8 lines long: fruit oblong, 4 to 8 lines long, 
2^ to 4^ lines broad, wdth wings usually more than half as 
broad as body, and filiform dorsal and intermediate ribs: oil-tubes 
usually solitary in the intervals (sometimes 2 in the lateral inter- 
vals), 2 or 4 on the commissural side. (Fig. 46.) — P. millefolium 
Watson, King’s Rep. v. 129, a name which must give way to the 
older P. millefolium of Bonder from S. Africa. 
Common on dry rocks, from N. Utah to Washington Territory. FI. 
March to May. 
It has been questioned whether certain forms with short leaf-segments 
are not entitled to rank at least as varieties, but we find the short and 
elongated leaf-segments often upon the same plant. When the segments 
become very much elongated and crowded the leaves strikingly resemble 
those of Leptotcenia purpurea. 
* * Plowers "white. 
11. P. macrocarpum Nutt. Ton*. & Gray, FI. i. 627. 
Somewhat caulescent or nearly acaulescent, foot or less high, more 
or less pubescent, from a long caudex terminating below in a fusi- 
form tuber: leaves bipinnate, segments pinnately incised, ultimate di- 
visions ovate or shortly linear: umbel somewhat equally 6 to 8-rayed, 
with involucels of conspicuous somewhat foliaceous lanceolate or 
linear biactlets, often united and unilateral; rays 1 to 3 inches long; 
pedicels 2 to 5 lines long; flowers mostly white (rarely yellow): 
calyx-teeth evident: fruit narrowly oblong, glabrous, 4 to 12 lines 
long, 2 to 3 lines broad, with wings about half as wide as body, 
and filiform dorsal and intermediate ribs: oil-tubes solitary in the 
intervals (often- obscure, rarely 2 or 3), 2 or 4 on the commissural 
