428 



ROSACEAE 



19. CHAMAERHODOS Bunge. 



Perennial or biennial herbs, with taproots, 2-4 times ternately divided 

 leaves, and small cymose flowers. Hypanthium cup-shaped, small. Petals and 

 sepals 5; bractlets wanting. Petals obovate or cuneate, somewhat clawed. 

 Stamens 5, opposite the petals; filaments subulate, short, persistent; anthers 

 didymous, opening by a sht. Pistils 5-10, or more; styles basal, filiform. Seed 

 inserted near the base of the style, ascending and nearly orthotropous. 



1. C. Nuttallii Pickering. Plant 1-3 dm. high, erect, branching and leafy, 

 hirsute and glandular; basal leaves numerous and rosulate, 2-4-ternately divided 

 into linear or oblong divisions; inflorescence many-flowered; hj'panthium 2-3 

 mm. in diameter, hispid; sepals narrowly lanceolate, equalling or somewhat 

 shorter than the white obovate-cuneate petals. C. ereda Hook., not Bunge. 

 Plains: Sask. — S.D. — Colo. — Alaska. Plain — Mont. Jl-Au. 



20. SANGUISORBA L. Burnet. 



Leafy perennial herbs, with thick rootstocks. Leaves odd-pinnate, with 

 adnate stipules and toothed leaflets. Flowers perfect or some of them pistillate, 

 in dense spikes. Hypanthium m-n-shaped, contracted at the mouth, angled, 

 and usually winged. Sepals 4, petaloid, deciduous, very concave. Petals none. 

 Stamens in ours 4, opposite to the sepals. Pistils solitary; styles terminal; 

 stigmas niLu-icate-papillose; ovule solitary, suspended. Achenes dry, enclosed 

 in the indurate 4-angled smooth hypanthium. 



1. S. sitchensis C. A. Meyer. Stem leafy, 2-12 dm. high; leaves odd-pin- 

 nate, the lower with 11-21 leaflets; leaflets 2-7 cm. long, 1.5-5 cm. wide, coarsely 

 serrate, rounded at the apex, those of the lower leaves deeply cordate at the base; 

 spike 2-10 cm. long, in age cyhndric; sepals oval, 2.5-3 cm. long, white or slightly 

 tinged with pm-ple. S. canadensis lalifolia Hook. Moist places: Alaska — 

 Yukon — Ida. — Wash. Submont. Jl-Au. 



21. POTERIDIUM Spach. 



Leafy branched annuals or biennials, with taproots. Leaves odd-pinnate, 

 with adnate stipules and pectinately pinnatifid leaflets. Flowers greenish, per- 

 fect, in dense, oblong spikes. Hj^panthium urn-shaped, contracted at the 

 mouth, 4-winged. Sepals 4, green, with white-scarious margins. Stamens 2 or 

 4, opposite to all or the inner two sepals; filaments short. Pistils solitary; stj'les 

 terminal; stigmas brush-like. Ovules solitary, suspended. Achenes enclosed 

 in the 4-winged, indm-ate, dry hypanthium. 



1. P. occidentale (Nutt.) Rydb. Stem branched, leafy, 2-10 dm. high; 

 leaves glabrous, odd-pinnate; leaflets of the lower leaves 11-15, obovate, the 

 larger 1-2 cm. long, pectinately pinnatifid into 9-15 narrowly linear acute divis- 

 ions; spikes globose to oblong-cylindric, 0.5-2.5 cm., or in fruit even 3-4 cm. long, 

 7-8 mm. thick; sepals oval, white-margined, green in the middle, 2 mm. long; 

 stamens 2, opposite the inner sepals; fruiting hypanthium lance-ovoid, 4-angled, 

 with narrow, thick wings, reticulate on the faces. Poteriuin annuum Hook., 

 not Nutt. Sanguisorba occidentalis Nutt. Moist places: Wash. — Mont. — 

 Ida. — Calif. Submont. Je-Au. 



2?. AGRIMONIA L. Agrimony. 



Perennial herbs, with rootstocks. Leaves odd-pinnate, with smaller leaflets 

 interposed between the larger ones. Flowers in narrow racemes, regular, perfect. 

 Hypanthium hemispheric to obconic, constricted at the throat and enclosing 

 the achenes in fruit, usually 10-grooved longitudinally, above with a ring of 

 hooked bristles. Sepals 5, after anthesis more or less connivent, forming a nipple- 

 shaped beak on the fruit. Petals 5, small, yellow, clawless. Stamens 5-15; 

 filaments slender. Pistils 2; styles terminal; stigmas 2-lobed; ovules suspended. 



Fruiting hypanthium with several series of bristles, the lower bristles reflexed; sepals 

 acuminate with tips incurved in fruit. 1. A. gryposepala. 



Fruiting hypantliium with 2^ series of bristles, the latter erect, ascending or merely 

 spreading; sepals acute. 2. A. striata. 



