Parr 3, 1908] ROSACEAE 271 
VI. TRIDENTATAE. 
Petals white, oblanceolate ; filaments linear-lanceolate ; cymes rather fas- 
tigiate. 
Petioles and stem with spreading hairs; leaflets toothed at the apex. 28. HY. tridentata. 
Petioles and stem appressed-silky ; leaflets entire. 29. H. integrifolia. 
Petals yellow, at least in drying. 
Cymes subcapitate ; outer filaments triangular to lanceolate. 30. A. flavescens. 
Cymes few-flowered and open ; filaments linear-lanceolate. 31. H. congesia. 
2s VII. HIRSUTAE. 
Cyme fastigiately corymbose. 
Leaflets oblong-cuneate, 2-5-toothed or cleft at the apex. 
Plant silky. 
Leaflets about 4 pairs, toothed at the apex. 31. HY. congesta. 
Leaflets 6-8 pairs, cleft with lanceolate divisions. 32. HY. pulchra. 
Plant hirsute ; leafiets 4-10 pairs. 33. Al. hirsuta. 
Leaflets divided to near the base into linear segments. 
Stem more or less glandular ; segments linear, acute, 1-2 mm. wide. 34. H. dauctfolia. 
Stem silky-villous, not glandular; segments narrowly linear, less 
than 1 mm. wide. 35. Hf. caruifolia. 
Cyme open and lax. 
Leaflets cuneate, cleft at the apex half their length into oblong-acute 
segments. 36. HY. laxiflora. 
Leaflets divided to the base into oblong or oval segments. 37. H. Howelltt. 
I, Californicae. Stout, glandular, leafy plants, with comparatively large leaflets. 
Flowers in aleafy cyme. Hypanthium deeply campanulate; bractlets ovate, much exceed- 
ing the sepals and petals. Petals narrow, strap-shaped, white. Stamens with rather long 
anthers and short, oblong, comparatively narrow filaments. 
1. Horkelia frondosa (Greene) Rydb. Bull. Torrey 
Club 25: 54. 1898. 
Potentilla frondosa Greene, Pittonia 1: 300. 1889. 
Perennial; stem stout, erect or decumbent, 0.5-1 m. high, densely glandular-hirsute and 
heavy-scented, leafy throughout; stipules ovate, about 1.5 cm. long; leaves pinnate, 
the lower with 3-4, the upper with 1-3 pairs of leaflets, more or less glandular-villous; 
leaflets ovate to oblong, 3-5 cm. long, doubly serrate, with mostly rounded teeth, the upper 
generally more or less confluent; cyme spreading and leafy; pedicels very short, 1-3 mm. 
long, seldom longer ; hypanthium campanulate, in fruit 5-6 mm. in diameter, more or less 
tinged with brown; hbractlets ovate, 3-5 mm. long, generally 3:toothed at the apex, spread- 
ing, a little exceeding the triangular-lanceolate sepals, which are erect in fruit; petals 
white, oblong, a little shorter than the sepals; stamens with flat oblong filaments and 
oblong anthers. 
TYPE LOCALITY : Martinez, Contra Costa County, California. 
DISTRIBUTION: Central California, near the coast. 
ILLUSTRATION : Mem. Dep. Bot. Columbia Univ. 2: pl. 56. 
2. Horkelia californica Cham. & Schlecht. Linnaea 2: 26. 1827. 
Sibbaldia californica Spreng. Syst. 42: 341. 1827. 
Horkelia grandis H. & A. Bot. Beech. Voy. 339. 1838. 
Potentilla californica Greene, Pittonia 1: 100. 1887. : 
Potentilla californica carmeliana Jepson, Fl, W. Middle Calif, 282. 1901. 
Root perennial; stems stout, 0.5-1 m. high, densely glandular and very fragrant, as 
well as the foliage, leafy; basal leaves numerous, long-petioled, pinnate; leaflets 5-10 
pairs ; stem-leaves smaller, the leaflets more crowded, all densely glandular-hirsute ; leaf- 
lets 2-5 cm. long, broadly obovate or orbicular in outline, toothed and incised, sometimes 
3-5-cleft with mostly acute teeth, the upper often confluent; inflorescence open, cymose- 
dichotomous; pedicels short, 2-5 mm. jong; hypanthium campanulate, in fruit about 1 
cm. in diameter, densely glandular and veined, often purple-tinged; bractlets 5-10 mm. 
long, ribbed, ovate and generally 3-toothed at the apex, the middle tooth the longest, 
somewhat exceeding the ovate, acute sepals; bractlets and sepals generally erect in fruit ; 
petals white, strap-shaped, oblong, much shorter than the sepals; stamens 10, with oblong 
filaments and anthers; stipules about 1 cm. long, ovate, generally more or less toothed. 
TYPE LOCALITY : San Francisco, California. 
DISTRIBUTION: Central California, near the coast. 
ILLUSTRATION : Mem. Dep. Bot. Columbia Univ. 2: pl. 57. 
