Part? 3, 1908] ROSACEAE 283 
3. Horkeliella Congdonis Rydberg. 
Horkelia Congdonis Rydb. Bull. Torrey Club 26: 543, 1899. 
Perennial, with a woody caudex; stems erect, 3-4 dm. high, few-leaved, somewhat 
branched above, glandular-puberulent; basal leaves 1-1.5 dm. long, with 30-40 pairs of 
leaflets ; stem-leaves similar but smaller ; upper stipules deeply cleft ; leaflets 3-5 mm. long, 
cleft to the base into 4-5 oblong divisions, obtuse, glandular-puberulent ; cyme with a few 
ascending branches and short-pedicelled flowers; hypanthium campanulate, 7-8 mm. in 
diameter in fruit, glandular-puberulent; bractlets lanceolate, one-half or two-thirds the 
length of the lanceolate acuminate sepals; petals almost equaling the sepals,’ oblong, 
obtuse ; filaments slightly dilated, subulate; pistils numerous. 
TYPE LOCALITY : Casa Diabolo, California. 
DISTRIBUTION : Known only from the type locality. 
16. IVESIA T. &. G. in Newb. Pacif. R. R. Rep. 6°: 72. 1857. 
Perennial, with thick erect rootstocks, and short, often woody caudices. Leaves mostly 
basal and numerous, pinnately divided, usually into numerous, small, more or less crowded 
and imbricate leaflets. Inflorescence cymose, open or dense. Hypanthium from deeply 
campanulate or turbinate to saucer-shaped. Bractlets, sepals, and petals 5. Petals usually 
oblanceolate and more or less clawed but sometimes nearly orbicular and practically claw- 
less, white or yellow. Stamens 5-20, inserted in the throat of the hypanthium and there-~ 
fore separated from the receptacle by an open space; filaments filiform, except in /. argy- 
yvocoma, in which they are subulate and slightly dilated. Receptacle from hemispheric to 
flat, usually poorly developed and bearing 3-15 pistils surrounded by a ring of prominent 
bristles. Styles long and slender, terminal or nearly so, sometimes slightly thickened and 
glandular below. Ovules and seeds pendulous and anatropous. 
Type species, Horkelia Gordonii Hook. 
Leaflets numerous, more or less crowded, often imbricate, generally divided to near the base. 
Stem leafy (less so in /. campestris and J. callida) ; stamens 15-20. 
Cyme corymbiform or subcapitate ; petals obovate with long claws. I, UNGUICULATAE. 
Cyme generally open with lax branches; petals with very short claws 
if any, white. II. EREMICAE. 
Stems few-leaved or scapiform ; stamens 5-10. III. LyYCOPpoDIoIpDES. 
Leaflets comparatively few, broadly obovate to reniform-flabelliform, merely 
coarsely toothed or incised. IV. SETOSAE. 
I. UNGUICULATAE. 
Whole plant silvery-white ; leaf-segments oblong ; stamens 20. 
Filaments somewhat dilated ; flowers in small subcapitate clusters. 1. Z. argyrocoma. 
Filaments not dilated ; cyme corymbose. 
Petals white. 2. I. sericoleuca. 
Petals yellow. 3. L. Pickeringti. 
Plant somewhat silky, but not silvery-white. . 
Petals white ; leaflets 5-10 mm. long ; stamens normally 15. 4. Lo unguiculata, 
Petals yellow ; leaflets less than 5mm. long; stamens 20. . 
Stems decumbent; petals spatulate. 5. Z, campesiris. 
Stems erect or ascending ; petals flabelliform-spatulate. 6. £. mollis. 
Il. EREMICAE, 
Petals orbicular or broadly obovate ; plant 2-4 dm. high. ; ; 
Leaflets generally simple, 2-ranked, more or less appressed-hirsute. 7. [, evemua. 
Leaflets generally divided, perfectly glabrous. 8. I, Kingit. 
Petals elliptic ; plant less than 1 dm. high. 9. I. callida, 
III. LYCcOPODIOIDES. 
Leaflets not bristle-tipped. : ; 
Leaves densely white-silky, appearing worm-like from the very small 
numerous imbricate leaflets. _ 
Plant 2-4 cm. high; bractlets ovate ; petals cuneate. 10. LZ. Muirti, — 
Plant 7-16 cm. high; bractlets linear ; petals linear. ll. L. Chandleri. 
eaves green. . 
. eaves slightly silky ; leaflets 8-10 pairs, 1-2 cm. long. 12, I. Webberi. 
Leaves glandular-pubescent or glabrate ; leaflets numerous. 
Cyme corymbiform ; hypanthium cupulate. 
Bractlets linear ; petals spatulate. ; 
Stems decumbent ; segments of the leaves oblong to spatulate, 13. 7, ulahensis. 
Stems erect ; segments of the leaves linear. 14. L. Tweedyi. 
