98 ROSACEAE, 
ExocHorpA, Pearl Bush. 
Deciduous shrubs with brownish wood with minute diffused 
ducts, somewhat more crowded in spring, and fine medullary 
rays; moderately slender terete twigs; round homogeneous pale 
pith; alternate slightly raised crescent-shaped leaf-scars with 3 
bundle-traces; no stipule scars; oblong ovoid sessile solitary 
erect buds, with about 8 exposed scales; moderate simple entire 
or few-toothed rather short-stalked leaves; rather large perfect 
polypetalous perigynous green-centered white flowers clustered 
at ends of the branches; and small star-shaped bony fruits. 
Leaves nearly elliptical, whitened beneath. E. racemosa. 
SIBBALDIA, 
Small matted perennials, woody only at base, with palmate 
trifoliolate long-petioled basal leaves; small perfect polypetalous 
yellow flowers in stalked corymbose clusters; and several akenes 
in each persistent calyx. 
Leaflets cuneate, crenately toothed at end. S. procumbens. 
POTENTILLA, Cinquefoil. 
Usually perennial herbs; a few deciduous shrubs with 
brownish wood with minute diffused ducts, somewhat more 
sparse in summer, and fine medullary rays; somewhat angular 
brown continuous pith; alternate minute round raised leaf-scars 
with a single bundle-trace, flanked by persistent stipules; small 
ovoid buds; compound leaves with several rather small leaflets; 
perfect open usually yellow polyetalous perigynous flowers with 
bractlets on the calyx; and numerous small akenes. 
Leaves pinnate: leaflets linear, entire. P. fruticosa. 
Leaflets palmate, 3, notched at end. P. tridentata. 
DryAs. 
Small matted trailing woody evergreens with rather small 
alternate slender-stalked simple leaves, white-woolly beneath; 
rather large perfect open polypetalous perigynous flowers soli- 
tary at ends of long erect stalks; and large clusters of long 
feathery-tailed akenes. 
