MEMOIRS FEOM THE DEPARTMENT OP BOTANY OF COLUMBIA UNIVERSITY 145 



Potentilla unguiculata Greene, Fl. Fran. 1 : 68. Mainly. 1891. 



Illustrations: Plate 55,/. 1; dissection of flower,/. 2; pistil,/ S ,- stamen,/ 4; 

 fruiting hypanthium and calyx, / 5. 



Root very thick, crowned with a short rootstock covered with brownish, densely 

 yellowish-hairy scales. Stems several, 3-4 dm. high, erect or ascending, branched, silky- 

 villous and rather leafy. Stipules lanceolate, 1-2 dm. long, often pectinately cleft. Basal 

 leaves numerous, 1-2 dm. long, densely white-silky, pinnate ; leaflets numerous, gen- 

 erally over 30, crowded and more or less imbricated ; petioles and lower part of the 

 stem silky-villous with long and reflexed hairs ; leaflets .5-1 cm. long, divided to the base 

 into oblong segments. Cyme much branched, many-flowered, at first rather dense, in age 

 open, more or less flat-topped. Hypanthium cup-shaped or campanulate, 3-5 mm. in di- 

 ameter ; bractlets oblong or lanceolate, about a third shorter than the ovate-lanceolate or 

 triangular sepals. Petals white, broadly obovate, clawed, much exceeding the sepals. 



This species was described by Brewer and Watson in the Botany of California under 

 the name Ivesia unguiculata and has since gone under that name. It is evidently very 

 distinct from the original I. unguiculata of Gray. It is much nearer related to H. Pick- 

 eringii from which it differs mainly in the more robust habit, white petals and slightly 

 longer pedicels. It is a native of the Sierra Nevada of Central California. Speci- 

 mens examined : 



California,: J. G. Lemmon, Nos. 11, 12 and 71, 1874; No. 95, 1875; C. F. Sonne, 

 Nos. 6 and 353, 1886; T. S. Brandegee, 1887. 



33. Horkelia Pickeringii (Gray). 



Ivesia Pickeringii Gray, Proc. Am. Acad. 6: 531. 1865. 



Torr. Bot. U. S. Expl. Exp. 288 ; Wats. King's Rep. 5 : 448 ; Brewer & Wats. Bot. 

 Cal. 1: 182; Torr. & Gray in Newberry, Pac. R. R. 6^: 72 (name only); Rattan, An. 

 Key W. Coast Bot. 52; Howell, FL N. W. Am. 1 : 181. 



Potentilla Pickeringii Greene, Pittonia, 1 : 105. 1887. 



Greene, Fl. Fran. 1 : 68. 



Illustrations: Bot. U. S. Expl. Exp. pi. 4- Plate 86, f. 1-2; dissection of 

 flower, / 3; stamen, /~ 4; pistil, / 5; fruiting hypanthium and calyx, / 6. 



Root deep and thick, crowned by a short erect rootstock covered with brown hairy 

 scales. Stems erect and ascending, 2-4 dm. high, finely villous, more or less leafy, di- 

 chotomously branched. Stipules lanceolate. Leaves numerous, grayish or white silky- 

 villous, pinnate with very numerous, crowded and somewhat imbricated leaflets, these 



