BUTTERCUP FAMILY 533 



Leaves (or some of them) toothed, lobod or diviiled. 



Herbage glabrous or nearly so; aehenes thick or plump. 

 Perennials; low plants; alpine or northern. 



Basal leaves nearly or quite as broad as long, rounded or truncate at base, 



Slobed at apex or entire _ 7. R. glaberrimus. 



Basal leaves broader than long, subcordate, 3 (or 5) -parted and coarsely 



toothed 8. a. cschscholtzii. 



Annuals; stems fistulous 9. B. soeleratus. 



Herbage pubescent or hirsute; leaves lobed or divided, mostly compound; perennials. 

 Beak of the aehenes commonly curved, much shorter than the body, rarely as long. 

 Stems commonly rather coarse, mostly erect and rather tall; aehenes strongly 

 flattened. 



Corolla pale or whitish, very small ; beak of aehene like a grab-hook 



10. B. bongardii. 

 Corolla golden, showy; sepals reflexed. 



Beak deltoid, slightly curved at the acute tip; petals 5 to 10 



11. B. ean/us. 

 Beak narrowly or broadly subulate, not deltoid. 



Petals 9 to 16; beak very short, stoutish, rather closely recurved.... 



12. E. cfilifornicus. 

 Petals 5 or 6; beak rather slender, falcate-curved but more or less 



erect 13. B. occidentaJis. 



Stems creeping or reclining; aehenes roundish or turgid, the beak curved or, 

 if straight, at least hooked at tip; sepals not reflexed. 

 Corolla showy; aehene margined; beak somewhat recurved ..14. B. rcpens. 

 Corolla small; aehene not margined; beak nearly straight ..15. B. maeounii. 

 Beak of the aehenes straight, as long as the body; sepals reflexed; stems spread- 

 ing or ascending. 

 Leaflets toothed or laciniate. 



Petals 5, emarginate; leaflets crenate, mostly not lobed --16. B. bloomeri. 



Petals 5 to 8, rounded at apex ; leaflets deeply 3-clef t or laciniate 



17. B. ortlwrhyncTms. 



Leaflets or their divisions with entire margins, not serrate or laciniate 



18. B. marmorarius. 

 Aehenes prickly or with stifiish hooked hairs; annuals. 



Flowers minute; aehenes with hooked hairs; delicate plant 19. if. hchecariius. 



Flowers medium; aehenes spiny -muricate, with raised border. 



Leaves cleft into 3 to 5 lobes, the lobes toothed; border of aehene beveled, not 



.sjiiny 20. E. muricaius. 



Leaves deeply 2 or 3 times divided; border of aehene spiny 21. R. arvcnsis. 



2. Aehenes utricular or tcUh a thin coat; perenniaJ-s. 



Leaves much dissected; flowers pink; aehenes strongly inflated. — Subgenus Crvmodes 



22. B. andersonii. 



Leaves cordate, lightly crenate; flowers yellow; aehenes thin-walled, striate; receptacle elon- 

 gated-oblong; stems creeping. — Subgenus Halodes 23. B. cymhaJaria. 



B. Nectar-bearing pit on petal claws naked; leaves or some of them filiform-dissected; 

 flowers white; aquatic. — Subgenus Batr.\chium. 



Leaves immersed, all filiform-dissected, or rarely some floating leaves 3-parted into broad 

 rounded lobes 24. B. aquatilis. 



Leaves floating, with 3 broad divergent narrowly ovate lobes, or some submersed leaves capil- 

 lary-dissected 25. B. lohbii. 



1. R. delphinifolius Torr. Yellow W.\ter Crowfoot. Aquatic iK'rennial; 

 steins fistulous, 1 to l! feet long; leaves three or four times teruately dissected 

 into linear-filiform acuminate segments; flowers golden-yellow, showy (8 to 13 

 lines broad), on naked fistulous peduncles % to 21,4 inches long; petals 5 or 6, 

 broadly obovate; scale of the nectary pit prolonged upwards into narrow or broad 

 wings attached l)y one edge to the petal and often with free ti]>s, the wliole 

 structure conspicuous, 1,4 to i/j as long as the petal, but apparently variable in 

 form and size: aehenes turgid, callous-margined at base and veiiti-ally with a 

 tumid ridge, % line long, tlie subulate bi'ak over half as long. 



