422 



ROSACEAE 



5. I. campestris. 



6. /. unguiculata. 



7. 



8. 

 9. 



I. Pickeringii. 

 I. sericoleuca. 

 I. Kingii. 



by a ring of bristles. Styles terminal or nearly so, long and slender. Ovules and seeds 

 pendulous and anatropous. [Name in honor of Dr. Eli Ives.] 



A west American genus of about 20 species. Type species, Ivcsia Gordonii (Hook.) Torr. & Gray. 



Pistils solitary; anthers opening by subterminal pores; leaflets closely imbricate, densely silvery-silky; stamens IS. 



1. 7. santolinoides. 

 Pistils 2 to many (rarely reduced to 1) ; anthers opening by longitudinal slits. 



Stamens 15 or 20. 



Inner row of stamens inserted at the edge of the receptacle; stamens 20; cespitose dwarf plants, with 

 few-flowered cymes. 



Petals white, obovate, equaling the sepals. 2. I. callida. 



Petals yellow, linear, much shorter than the sepals. 3. I. Jaegeri. 



Inner stamens inserted some distance from the edge of receptacle; stamens IS or 20. 



Filaments dilated below; leaflets closely imbricate, densely silvery-silky; stamens 20. 



4. I. argyrocoma. 

 Filaments slender, not dilated below. 



Plants tomentose or villous-tomentose, hypanthium campanulate. 

 Pistils 9-12; petals yellow. 

 Pistils 2—7; petals cream-colored or white. 

 Stamens IS; petals white. 

 Stamens 20; petals cream-colored. 



Pistils 2 or 3; hypanthium pilose within. 

 Pistils 4-7; hypanthium glabrous within. 

 Plants glabrous or essentially so; hypanthium saucer-shaped. 

 Stamens S or 10: 



Stamens 10; leaflets finely glandular-puberulent. 

 Stamens 5. 



Inflorescence of corymbose or subcapitate cymes; leaflets divided to near the base. 

 Leaves silky-pubescent. 



Leaves vermiform with minute closely imbricate and densely white-silky leaflets. 



11. I. Muirii. 

 Leaves not vermiform; leaflets not densely imbricate, somewhat silky-pubescent but green- 

 ish, 10-20 mm. long. 12. /. Webberi. 



Leaves glandular-pubescent or glabrate. 

 Leaflets not bristle-tipped. 



Hypanthium shallowly cupulate; petals exceeding the sepals. 13. I. Tweedyi. 

 Hypanthium campanulate; petals usually much shorter than the sepals. 

 Pistils 1-5, usually 2; styles filiform elongated, not glandular. 



14. I. Gordonii. 

 Pistils 9-20; styles short, glandular. 15. I. lycopodioides. 



Leaflets bristle-tipped, densely glandular-pubescent. 16. /. Shockleyi. 



Inflorescence an open lax cyme; pedicels very slender; leaflets merely toothed or incised. 



17. /. Baileyi. 



1. Ivesia santolinoides A. Gray. Mouse-tail Ivesia. Fig. 2398. 



Ivesia santolinoides A. Gray, Proc. Amer. Acad. 6: 531. 1865. 



Potentilla santolinoides Greene, Pittonia 1: 106. 1887. 



Stellariopsis santolinoides Rydb. Mem. Dept. Bot. Columbia Univ. 2: 155. 



10. I. pygmaea. 



1898. 



Stems several, erect, from a short erect caudex, hairy toward the base. Basal leaves 3—10 cm. 

 long, densely silky, terete and resembling a mouse-tail from the minute numerous densely imbri- 

 cated leaflets ; cyme much branched, open, the branches and pedicels very slender ; hypanthium 

 3 mm. broad in fruit, sparsely pubescent; sepals 1.5 mm. long, twice the length of the minute 

 bractlets; petals white, broadly ovate, twice as long as the sepals; stamens 15, filaments filiform; 



pistil 1. 



Dry, gravelly open places, Transition Zone; Sierra Nevada to the San Bernardino Mountains, California. 

 Type locality : Sierra Nevada, California. June-Aug. 



2390 

 2390. Horkelia tenuiloba 



2391 

 2391. Horkelia hispidula 



2392 

 2392. Horkelia Hendersonii 



