CROWFOOT FAMILY 199 



II. ECHINELLA. 



Achenes with spines on the faces or margins. 



Mature achenes 5-7 mm. long, the spines straight; petals at least 4 mm. long. 



Achenes with the margins produced into long spines. 12. R. arvensis. 



Achenes without spines on the margins, the faces spiny. 13. R. muricatus. 



Mature achenes 1-2 mm. long, the papillae on the faces produced into hooked spines; petals 1-2 mm. long. 



14. R. parviflorus. 

 Achenes with no spines, the faces papillate, 1-2 mm. long. 



Petals 1-2 mm. long, inconspicuous; papillae of the achenes produced into hooked hairs. 



J. J . jfV, ftcOcCdTpii'St 



Petals 8-9 mm long and conspicuous; papillae of the achenes not produced into hairs. 



16. R. sardous 



III. Epirotes. 



Receptacle and head of achenes cylindrical or ovoid. 



Nectary scale ciliate, the adjacent petal surface sometimes bearing similar hairs; achenes pubescent. 

 1 17. R. caraiopliyllHS. 



Nectary scale and the petal glabrous; achenes nearly always glabrous in Pacific States' varieties. 



Achene bodies almost oblong, the beaks about 1 mm. long, straight; petals when fully expanded at 

 least 60% longer than the sepals, 8-18 mm., rarely S mm. long; leaves truncate or rounded at 

 the base. 19 - R - Eschscholtzn. 



Achene bodies obovate, the beaks 0.3-0.5 mm. long, curving or recurved; petals when fully expanded 

 not exceeding the sepals by more than 20% to rarely 50%, 3-6 mm. long. 

 Radical leaves truncate to cuneate at the base; achene beaks curving, not markedly recurved. 



18. R. mamoenus alpeophilus. 



Radical leaves cordate at the base; achene beaks recurved. 20. R. verecundns. 



Receptacle and head of achenes spherical. 21. R. glaberrimus. 



IV. Flammula. 



Petals 5-10, conspicuous and usually large; perennials; achene beaks 0.3 mm. long or longer. 

 Cauline leaves lanceolate, oblanceolate, or linear. 



Roots not pubescent; petals exceeding the sepals. 



Stems prostrate, rooting at the nodes. 22. R. Flammula ovalis. 



Stems erect or reclining, never rooting. 23. R. alismaefolius. 



Roots pubescent; petals not exceeding the sepals, 3 mm. long by 1-1.5 mm. broad; stems never 



root i n g. 24. R. orestems. 



Cauline leaves ovate or ovate-lanceolate. 



Stems rooting at least at the lower nodes ; flowers never in cymes. 

 Roots with no thickening at the bases. 



Stems not fistulous or inflated, 1-1.5 mm. in diameter; cauline petioles sheathing the stem. 



22. R. Flammula samohfohus. 



Stems usually fistulous; usually 1.5-4 mm. in diameter; cauline petioles not sheathing the 

 stem. 25. R. hydrocharoides. 



Roots each with a light-colored, fusiform thickening at the base; stems filiform, 1 mm. thick. 



26. R. Gormann. 



Stems never rooting; flowers usually in cymes; roots each with a light-colored fusiform thickening 

 at the base. 27. R. Populago. 



Petals 1-3, minute, 1-1.5 mm. long; annuals; achene beaks 0.1-0.2 mm. long. 



Sepals 5; achenes papillate on the faces; upper cauline leaves linear to lanceolate or oblanceolate or very 

 narrowly elliptic, sessile. 28. R. pusillus. 



Sepals 3; achenes reticulate on the faces; upper cauline leaves ovate, petioled. 



29. R. alveolatus. 



V. Hecatonia. 



Styles and achene beaks practically lacking, the stigmas sessile; achenes without corky thickening of the peri- 

 carp, marked on each face with either rough transverse ridges or a circle of "pin pricks. 



30. R. sceleratus. 



Styles and achene beaks well developed, the beaks at least half as long as the bodies, 0.6-1.5 mm. long; achenes 

 with conspicuous corky thickening of either the keel or the pericarp beside the keel, otherwise smooth. 

 Achenes each with corky thickening beside the inconspicuous keel (especially in the basal and ventral 

 regions); leaves once- or twice-parted or -lobed, pentagonal, 1-2 cm. long by 1.5-2.5 cm. broad; anthers 

 elliptic, 0.5-1 mm. long; petals 4-7 mm. long. 31. R. Purslm. 



Achenes each with a conspicuous corky keel; leaves of aquatic specimens finely dissected into ribbon-like 

 segments 1-2 mm. broad, the blade 1.5-10 cm. long by 2-12 cm. broad; anthers oblong, 1-1.5 mm. long; 

 petals 7-15 mm. long. 32. R. flabellarts. 



VI. Halodes. 



A single species. ^^- R- Cymbalaria saximontanus. 



VII. Arcteranthis. 



A single species. 34. R. Cooleyae. 



VIII. Pseudaphanostemma. 

 A single species. 35. R. hystriculus. 



IX. EUCRYMODES. 

 A single species. 36. R. Andersonii. 



X. Eubatrachium 



Style in anthesis 2-3 times as long as the ovary; receptacle glabrous. 37. R. Lobbii. 



Style in anthesis about half as long as the ovary; receptacle hairy. 38. R. aquatilis capillaceus. 



1. Ranunculus acris L. Meadow Buttercup. Fig. 1822. 



Ranunculus acris L. Sp. PI. 554. 1753. 



Perennial, stems several, erect or suberect, 5-10 dm. high, stout, hirsute. Basal leaves 

 pentagonal, by forking of the two lateral lobes, 4-8 cm. long by 6-10 cm. broad, deeply parted 



