ROSE FAMILY 



423 



2. Ivesia callida (Hall) Rydb. Tahquitz Ivesia. Fig. 2399. 



Potentilla callida Hall, Univ. Calif. Pub. Bot. 1 : 86. 1902. 



Ivesia callida Rydb. N. Amer. Fl. 22: 286. 1908. 



Potentilla Shocklcyi var. callida Jepson, Man. Fl. PI. Calif. 492. 1925. 



Stems from a simple or cespitose caudex, spreading, leafy, 2-5 cm. long ; herbage glandular- 

 pubescent and hirsute. Basal leaves 1.5-3 cm. long; leaflets 6-8 pairs, crowded, 2-3 mm. long, 

 entire or divided into 2 unequal segments ; cyme few-flowered, open ; hypanthium about 2 mm. 

 wide, disciform; sepals lanceolate, 2.5-3.5 mm. long; petals white, obovate, equaling the sepals; 

 stamens 20, inserted close to the white-hirsute receptacle ; pistils 4-6 ; style glandular-thickened. 



A local species known only from Tahquitz Peak, San Jacinto Mountains, southern California. July-Aug. 



3. Ivesia Jaegeri Munz & Jtn. Jaeger's Ivesia. Fig. 2400. 



Ivesia Jaegeri Munz & Jtn. Bull. Torrey Club 55: 165. 1929. 



Stems from a short simple or cespitose caudex, decumbent, slender, 5-12 cm. long ; herbage 

 glandular-puberulent throughout. Basal leaves 3-8 cm. long; leaflets 4-8 pairs, rather distant, 

 3-6 mm. long, divided nearly or quite to the base into 2-5 oblanceolate or obovate segments; 

 cyme open, with few flowers on filiform pedicels; hypanthium disciform, about 2.5 mm. wide; 

 bractlets ovate, about 0.5 mm. long; sepals lanceolate, 2-3 mm. long; petals yellow, linear, 1 mm. 

 long ; stamens 20, the innermost on the rim of the hirsute receptacle ; pistils 3-9, style scarcely 

 glandular. 



Crevices of rocks Arid Transition Zone; Clark Mountains, San Bernardino County, California, and Charles- 

 ton Mountains, Nevada. Type locality : Charleston Resort, Charleston Mountains, Nevada. July-Aug. 



4. Ivesia argyrocoma Rydb. Silver-haired Ivesia. Fig. 2401. 



Horkelia argyrocoma Rydb. Mem. Dept. Bot. Columbia Univ. 2 : 144. 1898. 

 Ivesia argyrocoma Rydb. N. Amer. Fl. 22: 284. 1908. 



Stems decumbent or ascending, branching, about 2 dm. long, silky-villous, the lower part 

 and petioles covered with long, spreading, silvery hairs. Leaflets of basal leaves numerous, 

 densely imbricate, 3 mm. long, divided to the base into oblong segments, densely silky-pubescent ; 

 cyme dense, becoming open in age; sepals lanceolate-acuminate, 4 mm. long, exceeding the 

 oblong or lanceolate bractlets; petals white, broadly obovate, clawed, exceeding the calyx- 

 lobes ; stamens 20. 



Dry gravelly soils, Arid Transition Zone; San Bernardino Mountains, southern California. Type locality: 

 Bear Valley, San Bernardino Mountains. June-Aug. 



5. Ivesia campestris (M. E. Jones) Rydb. Field Ivesia. Fig. 2402. 



Potentilla utahensis var. campestris M. E. Jones, Proc. Calif. Acad. II. 5: 679. 1895. 

 Horkelia campestris Rydb. Mem. Dept. Bot. Columbia Univ. 2: 147. 1898. 

 Ivesia campestris Rydb. N. Amer. Fl. 22 : 285. 1908. 

 Horkelia mollis Eastw. Bot. Gaz. 41 : 286. 1906. 

 Potentilla campestris Jepson, Man. Fl. PI. Calif. 490. 1925. 



Stems several, ascending or decumbent, 1-2 dm. long, somewhat silky-villous. Leaflets of 

 basal leaves numerous, crowded, 3-4 mm. long, more or less silky-villous; cyme subcapitate; 

 hypanthium 5 mm. broad; sepals subulate-lanceolate, 2-3 mm. long; petals yellow, spatulate, a 

 little exceeding the sepals; stamens 15-20. 



Mountain meadows, Arid Transition and Canadian Zones; southern Sierra Nevada. Type locality: Whitney 

 Meadows, Sierra Nevada, California. June-Aug. 



2393 

 2393. Horkelia sericata 



2394 

 2394. Horkelia daucifolia 



2395 

 2395. Horkelia congesta 



