MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY 119 
Hemsley, Biol. Cent. Am. 1: 375; Don, Gard. Dict. 2: 559; Dietr. Syn. Pl. 3: 89; Walp. Ann. 2: 
472. 
Potentilla lineariloba Ser. in DC. Prodr. 2: 582. 1825. 
Lehm. Rev. Pot. 31; Don, Gard. Dict..2: 560; Dietr. Syn. Pl. 3: 189; Walp. Ann. 2: 472. 
Potentilla candicans nana Humb. & Bonpl.; Nestler, Mon. Pot. 34. 1816, 
Ser. in DC. Prodr. 2: 582; Lehm. Mon. 67; Rey. Pot. 31; Don, Gard. Dict. 2: 559; Walp. 
Ann. 2: 472. 
Potentilla Humboltiana Tratt. Ros. Mon. 4: 41. 
Perennial from a thick ligneous root and short caudex ; stem from .5 to 3 din. high with few re- 
duced leaves, more or less white-silky. Basal leaves numerous, silvery-white, pinnate, with 6-10 pairs 
of deeply dissected leaflets ; segments narrowly linear and more or less revolute. Bractlets oblong, 
about half as long as the ovate or broadly lanceolate sepals. Petals yellow, broadly obcordate, a little 
exceeding the sepals. Style filiform. 
The variety nana is only a depauperate form. The plant grows in mountain meadows of Central 
Mexico. 
State of Mexico: C. G. Pringle, No. 2923, 1889; No. 4176, 1896; F. Miller, No. 617, 1853 ; 
*Humboldt & Bonpland; *Coulter, No. 69; *Galeotti, No. 563; Schiede; E. W. Nelson, No. 197, 
1894. 
Potentilla candicans crocea Lehm. 
Potentilla candicans erocea Lehm. Rey. Pot. 32. 1868. 
Flowers orange. 
Mexico: Scheide, No. 585. 
2. HORKELIA Cham. «& Schlecht. 
Horkelia Cham. & Schlecht. Linnaea, 2: 26. 1827. 
Sibbaldia Sprengel, Syst. 4: part 2, 341. In part. 1827. 
Ivesia Torr. & Gray, Pac. R. R. Rep. 6: 72. 1857. 
Hypanthium deeply campanulate to saucer-shaped.  Bractlets, sepals and petals 5. 
Petals of variable form, strap-shaped, oblanceolate, obovate, cuneate or obcordate, often 
unguiculate, white or light yellow. Stamens 5-20, inserted in the throat of the hypan- 
thium and therefore separated from the receptacle by a wide open space ; filaments in 
Buwhorkelia and Horkeliella dilated and petaloid, persistent, triangular or lanceolate with 
a distinct midrib, in Jvesia filiform. Receptacle in the first two subgenera generally 
conic or hemispheric with numerous pistils, in the last mostly small or obsolete with 
3-15 pistils surrounded by a ring of prominent bristles. Styles long and slender, 
almost filiform, but generally slightly thickened and somewhat glandular below, articu- 
