416 ROSACEAE 



of 1 or 2 pairs, ovate to lanceolate, toothed, 5-10 mm. long; inflorescence flat-topped; petals 

 white, 5-6 mm. long ; achenes long-stipitate. 



Along streams, Humid Transition Zone; Coast Ranges of Oregon. Type locality: Trask River, Tillamook 

 County. June-Aug. 



10. *HORKELIA Cham. & Sch. Linnaea 2: 26. 1827. 



Perennial herbs with a thick woody caudex or rootstock covered with brown scales, 

 pinnate leaves, and cymose flowers. Hypanthium deeply campanulate to saucer-shaped; 

 bractlets 5, alternating with the 5 sepals. Petals variable, unguiculate, white or rarely 

 cream-colored. Stamens 10 or rarely 20, inserted in the throat of the hypanthium and 

 remote from the base of the receptacle; filaments dilated. Receptacle hemispherical or 

 conical with several to numerous pistils. Styles long and slender, generally thickened and 

 somewhat glandular at base, deciduous. Ovules and seeds pendulous, anatropous. [Name 

 in honor of John Horkel, a German physiologist.] 



About 30 species, natives of western North America, chiefly California. Type species, Horkelia californica 

 Cham. & Sch. 



Stamens 10; sepals erect or spreading. 



Bractlets ovate, simulating the sepals; pistils SO or more. 



Hypanthium cylindric-cupulate, 3-5 mm. deep; bractlets equaling or exceeding the sepals, often toothed. 



Hypanthium glabrous within; sepals green on inner surface. 



Leaflets 3-5 pairs, serrate; filaments opposite the sepals, lanceolate-deltoid. 



1. H. frondosa. 



Leaflets 5-10 pairs, deeply incised; filaments all essentially linear. 2. H. elata. 



Hypanthium pubescent within; sepals purple-flecked within. 3. H. californica. 



Hypanthium deeply saucer-shaped, 1.5-2 mm. deep; bractlets shorter than the sepals. 



Leaflets 5-10 pairs, the uppermost confluent. 4. H. cuneata. 



Leaflets 1-3 pairs, the terminal one petiolulate. 5. H. truncata. 



Bractlets lanceolate to linear, much smaller than the sepals. 



Pedicels recurved in fruit; cyme diffuse; hypanthium glabrous within. 



Hypanthium saucer-shaped, 5-6 mm. broad; pistils 17-30, rarely 50. 6. H. Parryi. 



Hypanthium cupulate, 3-4 mm. broad; pistils 3-4. 7. H. Wilderae. 



Pedicels erect, never recurved. 



Leaflets 5-20 pairs, the margin serrate to incised. 



Stipules of basal leaves not dissected; style glandular at base. 



Filaments glabrous. 



Hypanthium glabrous within. 



Petals cuneate, truncate or emarginate at apex; leaflets serrate to incised. 



8. H. fusca. 



Petals oblanceolate, rounded at apex; leaflets toothed at apex or palmately lobed. 



9. H. Clevelandii. 

 Hypanthium pubescent within. 



Leaflets serrate or shallowly lobed. 



Herbage appressed-villous and more or less hoary; montane species. 



10. H. Bolanderi. 



Herbage shaggy-villous; maritime species. 11. H. marinensis. 



Leaflets deeply palmatifid. 



Cymes compact, many-flowered; leaflets villous, 5—10 mm. long. 



12. H. tenuiloba. 



Cymes open, few-flowered; leaflets short-hirsute, 3.5-5 mm. long. 



13. H. hispidula. 



Filaments pubescent; herbage densely silky-villous. 14. H. Hendersonii. 



Stipules of basal leaves 2-4 times divided into filiform segments; style not glandular at base. 



Cyme diffuse; leaflets simply cleft or dissected; hypanthium turbinate. 



15. H. sericata.. 



Cyme compact; leaflets compoundly dissected; hypanthium shallowly cupulate. 



16. H. daucifolia. 

 Leaflets 2-5 pairs, entire or short-toothed only at apex. 



Petals emarginate or rarely rounded, well exceeding the sepals, and as broad or broader than 

 long, cream-colored. 17. H. congesta. 



Petals obtuse or rounded at apex, equaling or shorter than sepals and narrower than long, 

 white. 18. H. tridentata. 



Stamens 20; sepals reflexed in anthesis. 19. H. pxirpurascens. 



1. Horkelia frondosa (Greene) Rydb. Leafy Horkelia. Fig. 2379. 



Potentilla frondosa Greene, Pittonia 1: 300. 1889. 



Horkelia frondosa Rydb. Bull. Torrey Club 25: 54. 1898. 



Potentilla californica var. frondosa Jepson, Man. Fl. PI. Calif. 494. 1925. 



Stems leafy throughout, stout, erect or decumbent, 0.5-1 m. high, glandular-pubescent and 

 fragrant. Lower leaves with 7-9, the upper with 3-7 leaflets, glandular-villous ; leaflets 3-5 cm. 

 long, ovate to oblong, doubly serrate, with mostly rounded teeth ; bractlets ovate, 3-5 mm. long, 

 usually 3-toothed, slightly exceeding the triangular-lanceolate sepals ; petals oblong, shorter than 

 the sepals. 



Open slopes near the coast, Upper Sonoran and Transition Zones; San Francisco Bay region to Monterey, 

 California. Type locality: Martinez, Contra Costa County. May— Oct. 



* The keys and specific and subspecific limits in the genera Horkelia and Ivesia are based largely on 

 David D. Keek's able revision recently published. 



