114 FOUNDATIONS OF BOTANY 



X. POTENTILLA, L. 



Perennial herbs, rarely shrubs. Leaves compound ; stipules 

 adnate to the petiole. Flowers white or yellow, rarely red ; 

 solitary or in cymes. Calyx free from the ovary, 5-cleft, with 

 5 little bracts alternating with its lobes. Petals 5. Stamens 

 many. Carpels usually many, on a dry convex or concave 

 receptacle ; styles falling off from the akenes as they mature. 



1. P. arguta, Pursh. UPRIGHT CINQUEFOIL. An erect, stout 

 hairy plant, 1-4 ft. high. Root-leaves long-petioled, pinnate. Stem- 

 leaves few, each of 3-7 leaflets, the latter broadly ovate and cut- 

 toothed or serrate, downy underneath. Flowers large, in dense 

 terminal clusters ; the petals whitish or cream-cplor. Rocky hills. 



2. P. canadensis, L. COMMON CINQUEFOIL. Stems slender, pro- 

 cumbent, silky-hairy, sending out long runners. Leaflets obovate 

 wedge-shaped, appearing like 5 from the divisions of the 2 lateral 

 ones. Peduncles 1-flowered in the axils of the leaves. Flowers 

 yellow. Common in dry pastures and a troublesome weed. 



3. P. argentea, L. SILVERY CINQUEFOIL. Stems prostrate or 

 ascending and branching, woolly. Leaflets oblong, wedge-shaped, 

 those of the upper leaves very narrow, with a few large, deeply cut 

 teeth, smooth and green above, silvery beneath, with a dense coat of 

 white wool. Flowers small and somewhat clustered, yellow. Dry 

 fields and roadsides. 



XL GEUM, L. 



Erect perennial herbs. Radical leaves crowded, pinnate, 

 with a very large terminal leaflet. Flowers and fruit much 

 as in Potentilla, but the akenes tailed with the remains of the 

 styles. 



1. G. album, Gmelin. WHITE AVENS. Stem erect, branching 

 above, smooth or finely downy, 18-24 in. high. Radical leaves pin- 

 nate, or the earliest simple and rounded, long-petioled, serrate or 

 dentate, terminal lobe larger than the lateral lobes; stem-leaves 

 short-petioled, 2-5-lobed or parted. Flowers on slender peduncles. 

 Petals white, not longer than the sepals. Styles jointed near the 

 middle, the lower portion persistent and hooked. Ovaries and recep- 

 tacle hairy, head of fruit globose. Rich woods.* 



2. G. virginianum, L. Stem 2-3 ft. high, stout and bristly 

 hairy. Lower leaves and root-leaves pinnate, varying greatly; upper 

 leaves mostly of 3 leaflets or 3-parted. Petals white or pale yellow, 



