Part 3, 1908] ROSACEAE 269 
from pendulous and anatropous in genera with terminal style to ascending and 
orthotropous in genera with basal styles. 
A. Style terminal or nearly so; ovules pendulous and anatropous. 
Anthers oblong, opening by longitudinal slits ; pistils two to many. 
Stamens separated from the receptacle by an open space; no indication of an annular thick- 
ening at the base of the filaments. 
Hypanthium saucer-shaped to deeply campanulate ; petals oblanceolate to obcordate or 
cuneate ; pistils usually more than 2. 
Filaments dilated, petaloid. 
Stamens 10; sepals not reflexed in anthesis. 
Stamens 20. 
Pistils numerous ; hypanthium campanulate; sepals reflexed 
in anthesis. 
Pistils 3-6; hypanthium turbinate ; sepals not reflexed in 
anthesis. (One species, J. argyrocoma, in) 
Filaments filiform. 
Pistils inserted in the bottom of the hypanthium ; bractlets 
present. 
Pistils inserted on a stalked receptacle ; bractlets lacking. 
Hypanthium wheel-shaped ; petals narrowly linear ; pistils 2. 
Stamens inserted very near the base of the receptacle on a more or less 
evident annular thickening. 
Anthers obcordate, opening by subterminal pores ; pistil 1. 
B. Style lateral; ovules ascending and amphitropous. 
Achenes glabrous ; herbs. 
Achenes numerous ; stamens about 20. 
Leaves odd-pinnate. 
Receptacle not enlarged in fruit ; petals yellow, obtuse or retuse ; 
14. HORKELIA. 
15. HORKELIELLA. 
16. IveEsta. 
16. Ivestia. pie? [ 
17, Purpusta. P74). 
18. COMARELLA. 
20. 
19, 
POTENTILLA. 
STELLARIOPSIS. 
leaves interruptedly pinnate. 
Receptacle somewhat enlarged in fruit, becoming spongy ; petals 
: 22 
21. ARGENTINA. 
red, acute or acuminate ; leaves regularly pinnate. . COMARUM. 
Leaves trifoliolate ; receptacle much enlarged and usually red in 
fruit. : 
Receptacle not pulpy ; petals yellow. 23. DUCHESNEA. 
Receptacle pulpy ; petals white or pinkish. 24, FRAGARIA. 
Achenes 10-15 ; stamens 5; leaves trifoliolate. 25. SIBBALDIA. 
Achenes hairy; shrubs or undershrubs. 
Style filiform ; leaves trifoliolate; petals white. 26. SIBBALDIOPSIS, 
Style club-shaped ; leaves pinnate ; petals (in ours) yellow. 27. DASIPHORA. 
C. Style nearly basal ; ovules ascending or nearly erect, orthotropous. 
Stamens and pistils numerous ; bractlets present ; leaves pinnate. 28. DRYMOCALLIS. 
Stamens 5; bractlets wanting ; leaves twice or thrice ternate. 29, CHAMAERHODOS. 
14. HORKELIA Cham. & Schlecht. Linnaea 2: 26. 1827. 
Perennial herbs with scaly rootstocks or caudices. Leaves pinnately compound, usu- 
ally with many leaflets. Inflorescence cymose-paniculate. Hypanthium deeply campan- 
ulate to saucer-shaped. Bractlets, sepals and petals 5. Petals of variable form, strap- 
shaped, oblanceolate, obovate, cuneate or obcordate, often unguiculate, white or light- 
yellow. Stamens 10, inserted in the throat of the hypanthium and therefore separated 
from the receptacle by a wide open space; filaments dilated and more or less petaloid, 
persistent, triangular, lanceolate or subulate, with a distinct midrib. Receptacle generally 
conic or hemispheric with numerous pistils, in a few species small, with 3-15 pistils. Styles 
long and slender, almost filiform, but generally slightly thickened and somewhat glandular 
below, articulated to the achene and at last deciduous. Ovule and seed inserted near the 
base of the style, pendulous and anatropous. 
Type species, Horkelia californica Cham. & Schlecht. 
Lower stipules not dissected into linear-filiform segments. 
Cyme very leafy; hypanthium campanulate; bractlets ovate, much ex- 
ceeding the sepals and petals. 
Cyme less leafy ; hypanthium cupulate or saucer-shaped ; bractlets not 
exceeding the sepals. 
Leaves with 4-15 pairs of toothed or dissected leaflets. 
Bractlets ovate or lanceolate ; leaflets cuneate, toothed or divided, 
not densely imbricated; inflorescence truly cymose; filaments 
not very unequal in shape. 
Bractlets linear. . . 
Leaflets not densely crowded, nor imbricate; inflorescence 
dense, subcapitate or fastigiate. 
Petals oblong, rounded at the apex; filaments not very un- 
equal in shape. 
I. CALIFORNICAE. 
II, CUNEATAE. 
III. TENUILOBAE. 
