44 MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY 
17. Potentilla Michoacana. 
Spreading from an annual root, finely pubescent, divergently branched. Leaves ternate with 
shortly stalked terminal leaflets; leaflets narrowly cuneate, few-toothed above the middle, 1-2 em. 
long, finely puberulent. Bractlets oblong, about equalling the broadly ovate sepals. Petals white, ob- 
ovate, truncate, half the length of the sepals. Stamens 5. 
Mexico, State of Michoacan: C. G. Pringle, No. 5291. 1892. 
18. Potentilla biennis Greene. 
Potentilla rivalis var. millegrana Torr. U. 8. Expl. Exp. 17: 289. Not Wats. 
Coulter. U. S. Geol. Surv. 1872: 765; Coville, Cont. U. 8. Nat. Herb. 4: 96. 
(2) Potentilla millegrana Dougl.; Hook. Fl. Bor. Am. 1: 193, as synonym under P. 
Norvegica. 
Potentilla millegrana Wats. in King’s. Rep. 5: 85. In part. 1871. Not Engelm. 
1849. Holzinger, Cont. U. 8. Nat. Herb. 3: 223. 
Potentilla biennis Greene, Fl. Fran. 1: 65, 1891; Man. Bay Reg. 115. 
Potentilla lateriflora Rydberg, Bull. Torr. Bot. Club, 28: 261. 1896. 
Potentilla millegrana lateriflora Engelm. Rydberg, /. ¢. as synonym. 
IntustRAtTIoNs; Puate 9, f. 1; dissection of flower, f. 2; pistil, f. 3; stamen, f. 4; 
fruiting hypanthium and calyx, f. 5. 
Annual or biennial. Stems often several from the root, 83-5 dm. high, terete, finely 
and rather densely granular-pubescent, often tinged with red or purple, simpler than in 
related species and with erect branches. Stipules small, ovate or oblong, entire or 
toothed. Leaves all ternate, the lower with petioles 2-10 cm. long, more or less hairy ; 
leaflets broadly obovate, coarsely crenate, 2-4 cm. long and 1-3 em. wide, the teeth 
often mucronulate. Flowers small, about 5 mm. in diameter, on pedicels 5-15 mm. long 
from the axis of upper leaves, making the branches finally resemble leafy racemes. 
Hypanthium glandular-pubescent, in fruit about 5 mm. in diameter. Bractlets ovate- 
lanceolate or oblong, acute, a little shorter than the ovate acute sepals. Petals yellow, 
obovate-cuneate, sometimes slightly emarginate, shorter than the sepals. Stamens about 
10. Pistils very numerous; style terminal, thickened and glandular at the base; ripe 
achenes whitish, smooth. 
This most resembles P. /ewcocarpa and is often confounded with it in our herbaria. 
Sometimes it is labelled P. Norvegica, which it resembles in the form of the leaf and 
general habit, but is a much more slender plant and bas much smaller petals and fruit- 
ing calyx. From P. lewcocarpa it differs in the simpler and erect stems, erect branching, 
falsely racemose inflorescence, broader and more hairy leaflets, and more glandular stems. 
