5(3). Petals with a relatively small erect limb, produced below into a long 

 tapering hollow spur that is clavate at the end 3. Aquilegia 



5. Petals none, the sepals petal-like; flower rather simple 2. Caltha 



6(1). Petals present (except sometimes in Myosurus); leaves commonly alternate 

 or all basal (7) 



6. Petals none or rudimentary (8) 



7(6). Sepals spurred at base, the spur usually elongate, scarious; petals very 

 small or none; receptacle becoming greatly elongate with the fruits 

 in a slender cylindric spike; plants scapose 7. Myosurus 



7. Sepals not spurred; petals usually present, often showy; receptacle not becom- 



ing greatly elongate with the fruits in a conic to ovoid or hemi- 

 spheric head; stems commonly leafy 9. Ranunculus 



8(6). Sepals large and showy, petal-like, somewhat persistent; achenes globose 

 and with long often plumose tails 6. Clematis 



8. Sepals small, less conspicuous than the stamens, caducous; achenes without 



long plumose tails (9) 



9(8). Leaves simple, palmately lobed or parted; outer filaments flat, somewhat 



petaloid; anthers oval or ovate, about 1 mm. long 



8. Trautvetteria 



9. Leaves decompound; filaments all filiform; anthers narrowly linear, much 



more than 1 mm. long 10. Thalictrum 



1. Xanthorhiza Marsh. 



A monotypic genus. 



1. Xanthorhiza simplicissima Marsh. Brook-feather, yellowroot. 



Plant low, weak, shrubby, with deep-yellow and bitter bark and long roots, 

 to about 6 dm. high; leaves approximate, 1- or 2-pinnate: leaflets mostly 5, ovate 

 to elliptic, 25-75 mm. long, incised-toothed or divided; flowers polygamous, in 

 compound drooping racemes, appearing along with the leaves from large terminal 

 buds in early spring; sepals regular, 5, spreading, deciduous, ovate to ovate- 

 lanceolate, brownish-purple; petals 5, glandlike; stamens 5 or 10, the filaments 

 stout; pistils 5 to 15, with 2 pendulous ovules; follicles elliptic 1 -seeded, 3-4 mm. 

 long, the short style becoming dorsal. 



In damp woods, thickets and on wooded stream banks, often on the edge of 

 water, rare in s.e. Tex., Mar.-May; from N.Y., s. to Fla. and Tex. 



2. Caltha L. Marsh Marigold 

 About 20 species in Arctic and North Temperate regions. 



1. Caltha leptosepala DC. Elk's lip. Fig. 449. 



Glabrous perennial; petioles from shorter than to several times longer than 

 the blade; blades ovate-oblong to oblong, obtuse, bright green, to about 7 cm. 

 long and 4 cm. wide, subentire to serrate or dentate, the basal sinus mostly 

 open; scape to about 6 cm. long, usually with a single leaf and a solitary 

 peduncle mostly 3-10 or rarely to 20 cm. long; flower solitary; sepals 5 to 9, 

 petal-like, the inner surface white, the outer surface bluish; pistils 5 to 10, with 

 scarcely any styles; follicles compressed, spreading, somewhat stipitate. 



In wet meadows, marshes and wet soils about mt. lakes, below snow-banks and 

 along streams, in N.M. (San Juan, San Miguel and Taos cos.) and Ariz. (Apache, 

 Coconino and Graham cos.), June-Sept.; Mont, to Alas., s. to N.M., Ariz, and 

 Wash. 



915 



