358 UMBELLIFERAE (PARSNIP FAMILY) 



rise to a tuft of leaves and longer peduncles (occasionally bearing a small 

 leaf): leaves with the ultimate divisions linear: peduncles reaching a height 

 of 2-3 dm. ; umbel of unequal rays, no involucre, and involucels of small linear 

 bract Ids; rays 1-3.5 cm. long; pedicels 2-4 mm. long; flowers yellow: fruit 

 oblong, 6-7 mm. long, the dorsal and intermediate wings sometimes reduced 

 in breadth; oil-tubes 3-5 in the intervals, 6 or more on the commissural side: 

 seed face with broad and shallow concavity, but in immature specimens 

 sometimes appearing plane. Interior Wyoming to Nevada and Oregon. 



2. Pteryxia albi'flora Nutt. T. & G. Fl. 1: 625. 1840. Low, very leafy at 

 base: leaves pale, the ultimate segments divaricate and often 3-cleft, short, 

 acute: peduncles slender, more or less spreading, 1-1.5 dm. high, consid- 

 erably longer than the leaves; umbels with unequal rays, no involucre, and 

 involucels of several linear bractlets; rays 4-12 mm. long; fruiting pedicels 

 3 mm. long; flowers white: fruit nearly orbicular, 4 mm. long, each carpel 

 with usually 5 more or less undulate wings. Northern Wyoming, Idaho, and 

 Montana. 



20. THASPIUM Nutt. 



Perennials, with ternately compound leaves and broad serrate or toothed 

 leaflets (or lower leaves simple), mostly no involucre, involucels of small 

 bractlets, mostly yellow flowers, and all the fruits pediceled. Calyx-teeth 

 conspicuous. Fruit ovoid to oblong, mostly glabrous. Carpel with 3 or 4 

 or all the ribs strongly winged; stylopodium wanting; style long; oil-tubes 

 solitary in the intervals, 2 on the commissural side. Seed face plane. 



1. Thaspium trifoliatum aureum (Nutt.) Brit. Mem. Torr. Club 5: 240. 

 1894. Glabrous, 6-15 dm. high: basal leaves mostly cordate, serrate; stem 

 leaves simply ternate (rarely biternate); leaflets ovate to lanceolate, rounded 

 or tapering at base, serrate: umbels 8-12-rayed; rays 1-2.5 cm. long; pedicels 

 about 2 mm. long; flowers yellow: fruit globose-ovoid, about 4 mm. long, all 

 the ribs equally winged. T. trifoliatum in part. Wyoming and eastward. 



21. AULOSPERMUM C. & R. 



Caulescent or acaulescent plants, with more or less pinnately dissected 

 leaves (or primary division ternate), mostly no involucre, involucels of small 

 narrow bractlets, which are not at all hyaline, and white, yellow, or purple 

 flowers. Calyx-teeth evident. Fruit oblong to orbicular in outline, glabrous. 

 Carpel with 3-5 usually broad wings which are sometimes thickened at in- 

 sertion, and with narrow or broad intervals; stylopodium wanting; oil-tubes 

 several in the intervals, 2 or more on the commissural side. Seed not dor- 

 sally flattened or but slightly so, the face usually with a narrow and deep 

 sulcus. Cymopterus in part. 



Stems becoming caulescent, crowned with a cluster of leaves and pe- 

 duncles. 

 Flowers yellow. 



Leaves coarsely dissected . . . . . . . . 1. A. longipes. 



Leaves more finely dissected 2. A. angustum. 



Flowers white or purplish. 



Flowers white 3. A. ibapense. 



Flowers purple 4. A. planosum. 



Stems acaulescent . . . . . . . . . . 5. A. purpureum. 



1. Aulospermum longipes (Wats.) C. & R. Contrib. Nat. Herb. 7: 175. 

 1 'MM). Glabrous and glaucous: leaves pinnate to bipinnate, the ultimate seg- 

 ments oval and mucronulate: fruiting peduncles longer than the leaves, 

 10-25 cm. long; umbels 5-10-rayed, with no involucre, and involucels of sub- 

 icuiniiiate bractlets; rays 12-40 mm. long; pedicels 4-6 mm. long; 

 flowers yellow: fruit 6-8 mm. long, the 5 carpel wings broad and thin, some- 

 uhat unequal; oil-tubes 3-4 in the intervals, 6 on the commissural side: seed 

 iaec \\ith deep and narrow sulcus, which broadens into a central cavity. 

 Naked clay soils in the desert areas; Colorado, Utah, and W T yoming. 





