AMMIACEAE. 265 



the commissural side. Seed dorsally flattened with 

 plane or rarely slightly concave face. (Peucedanum.) 



Flowers yellow. 



Fruit 4-10 mm. long. 1. C. utriculata. 



Fruit 12-14 mm. long. 2. C. vaseyi. 



Flowers white. 3. C. dasycarpa. 



1. C. utriculata (Nutt.) Jones. Caulescent or nearly acaules- 

 cent, caespitose to 3 dm. high or more, from a more or less thickened 

 root, puberulent or glabrous; petioles very broadly dilated; leaves 

 ternately or pinnately decompound, with ultimate segments narrowly 

 linear 12 mm. or less long; umbel unequally 5-20-rayed; bracts much 

 dilated, mostly obovate, often toothed; rays 5 cm. long or less; 

 pedicels 4-10 mm. long; flowers yellow; fruit broadly elliptic, gla- 

 brous, 4-10 mm. long, 2-7 mm. broad, with wings nearly as broad 

 as the body, and prominent dorsal and intermediate ribs; oil-tubes 

 large, solitary in the intervals, 4-6 or sometimes 2-3 on the com- 

 missural side, very short accessory ones in the intervals; seed-face 

 somewhat concave. 



Frequent on the mesas and grassy foothills. 



2. C. vaseyi C. & R. Short, caulescent, 15-20 cm. high; slightly 

 pubescent; petioles wholly inflated; leaves small, 2.5-5 cm. long, 

 bipinnate, with the small ovate segments irregularly 3-5-lobed; 

 umbel equally 2-5-rayed; bractlets obovate, petiolulate, toothed; 

 rays 2.5 cm. long; pedicels 2-4 mm. long; flowers yellow; fruit 

 broadly oblong, emarginate, glabrous, 12-14 mm. long, 8 mm. broad, 

 with wings twice as broad as the body, and mostly prominent dorsal 

 and intermediate ribs; oil-tubes solitary in the intervals, 4 on the 

 commissural side. 



Frequent in heavy soil on the mesas throughout our range. 



3. C. dasycarpa (T. & G.) Jones. Very short, caulescent or 

 acaulescent, with several stout peduncles, 1,5-3 cm. long, from a 

 common root, tomentose-pubescent; leaves rather small, pinnately 

 decompound, with numerous short linear segments; umbel some- 

 what equally 6-15-rayed; bractlets linear to ovate, more or less 

 tomentose; rays 2.5-7.5 cm. long; pedicels 6-10 mm. long; flowers 

 white; fruit nearly orbicular, coarsely pubescent, becoming almost 

 glabrous, 8-14 mm. long, 7-12 mm. broad, with thin membranous 

 wings, broader than the body, and filiform dorsal and intermediate 

 ribs; oil-tubes large and solitary in the intervals (an occasional 

 secondary one in the lateral intervals), 4 on the commissural side; 

 seed deeply sulcate beneath the oil-tubes, with plane face. 



Occasional on dry hillsides, especially in the interior region. 



20. EURYPTERA Nutt. 



Acaulescent or caulescent glabrous perennials, with 

 elongated roots, branching only from the base, leaves 

 once or twice compound, with usually broad sharply 

 toothed leaflets. Flowers yellow. Calyx-teeth minute 



