408 ROSACEAE 



divided to near the base into obovate-oblong divisions; cyme much branched, 

 open; hypanthium 4 mm. broad, glandular-puberulent and sparingly hirsute; 

 petals yellow, shorter than the sepals, oblanceolate; stamens 5; pistils 2-7. 

 Mountains: Nev. 'Utah. Son. Submont. 



4. I. Gordonii (Hook.) T. & G. Perennial, with a thick and deep root and 

 short woody cespitose caudex; stem subscapose, minutely glandular-puberulent 

 or glabrous, 1-2 dm. high, seldom 3 dm.; basal leaves numerous, finely puberu- 

 lent or glabrate, pinnate; leaflets 10-20 rather approximate pairs, 5-12 mm. 

 long, divided into 3-5 segments or again divided; segments broadly oblong to 

 linear; hypanthium campanulate, 3-4 mm. in diameter, villous-puberulent and 

 somewhat glandular, yellowish; petals yellow, spatulate or oblanceolate, shorter 

 than the sepals. Mountains: Wash. -Calif. -Colo. Mont. Submont. Sub- 

 alp. Je-Au. 



6. I. beneolens (A. Nels.) Rydb. Perennial, with thick woody caudex 

 densely covered with remains of old leaves; stems several, 7-15 cm. long, viscid- 

 puberulent; basal leaves numerous, about 1 dm. long, with 5-9, obovate, flabelli- 

 form or suborbicular leaflets; these 5-15 mm. long, parted and incised into oblong 

 lobes, viscid-puberulent; stem-leaves with 3-5 smaller leaflets; flowers cymose; 

 hypanthium saucer-shaped, 5-angled, with a disk; sepals ovate; petals white, 

 linear-oblanceolate; stamens 5; pistils 3-5. Hookelia beneolens A. Nels. Crev- 

 ices of basalt cliffs: Ida. Son. Je. 



11. COMARELLA Rydb. 



Perennial herbs, with very thick woody taproots and short thick scaly cau- 

 dices. Leaves pinnate with numerous crowded leaflets. Inflorescence cymose- 

 paniculate, with slender branches. Hypanthium wheel-shaped, i. e., the central 

 portion turbinate, enclosing the ovaries, and beset on its inner surface with long 

 bristles, the lateral portion flat, pentagonal in outline. Petals dark purple, 

 narrowly linear, shorter than the calyx. Stamens 5, inserted at the outer mar- 

 gin of the flat portion of the hypanthium; filiments filiform, bent inward; anthers 

 small. Pistils two; styles long and filiform, terminal. 



1. C. sabulosa (M. E. Jones) Rydb. Stem several from the caudex, ascend- 

 ing, less than 2 dm. high, slender, glabrous ; leaves glabrate, pinnate; leaflets about 

 15 rather approximate pairs, 3-5 mm. long, 2-3-cleft into oval segments; hypan- 

 thium glabrous, 3-4 mm. in diameter, in age 5-angled; bract-lets linear-subulate, 

 thickish, much smaller than the ovate-lanceolate acuminate sepals. Potentitta 

 sabulosa M. E. Jones. Mountains: Utah. Son. Au-S. 



12. POTENTILLA L. CINQUEFOIL, FIVE-FINGER. 



Annuals, or perennial herbs, with rootstocks. Leaves pinnately or digitately 

 compound. Inflorescence usually cymose-paniculate. Hypanthium concave, 

 mostly hemispheric. Bractlets, sepals, and petals 5 (sometimes 4). Petals 

 deciduous, obcordate, obovate, rotund, or cuneate, as a rule not unguiculate, 

 yellow, white, or dark-purple. Stamens most commonly 20, in three series, viz., 

 10, 5, and 5, respectively, sometimes more, sometimes fewer; filaments filiform 

 or subulate, neither flattened nor dilated. Receptacle hemispheric or conic, 

 bearing usually numerous pistils. Style usually long and filiform, attached 

 near the apex of the ovary, deciduous. Seeds inserted near the base of the style, 

 pendulous and anatropous. 



Cymes very leafy, many-flowered; annuals or biennials, rarely short-lived perennials; 



styles fusiform and glandular at the base. I. SUPINAE. 



Cymes not very leafy, generally rather few-flowered; perennials with rootstocks. 

 Leaves digitate. 



Basal leaves 5-9-foliolate. 



Basal leaves without an additional pair of leaflets on the petioles. 

 Plants more than 2 dm. high. 



Leaves green on both sides, sparingly hairy, not at all tomentose. 



II. NUTTALLIANAE. 



Leaves either densely hairy or more or less tomentose beneath. 



Leaflets merely crenate or cut-toothed, the toothing not extending 

 half-way to the midrib. 



