Ranunculaceae 169 
BATRACHIUM WATER CROW-FOOT 
Herbs, annual or perennial, aquatic or subaquatic. Submerged leaves filiform-dis- 
sected; emersed leaves when present with flat blade; petioles with dilated stipule-like base. 
Peduncles solitary, opposite the leaves. Petals white, with yellowish base, with naked 
pit at base. Akenes not margined, transversely rugose. (Gk. batrachos—a frog; on 
account of the aquatic habitat. ) 
A. Leaves mostly submerged; styles not longer than the ovary. 
B. Some of the leaves commonly floating and not composed of filiform segments; 
leaf-segments |—2.5 cm. long. W.C.E. (Ranunculus aquatilis. ) 
B. aquatile Wimm. 
BB. All the leaves composed of filiform segments; leaf-segments 2.5——5 cm. long. 
W.C.E. (B. aquatile pantothrix; B. trichophyllum; B. aquatile caespitosum; B. 
fiaccidum. ) B. aquatile trichophyllum (Gray) (Ditch Crow-foot) 
AA. Leaves nearly all floating; styles about 3 times as long as the ovary. W. 
B. lobbii Gray 
RANUNCULUS BUTTERCUP 
Herbs, annual cr perennial, mostly in wet places, sometimes aquatic. Leaves sim- 
ple or compcund, alternate, entire or lobed or divided or dissected, or palmately or ter- 
nately compound. Flowers yellow or red. Sepals 5, deciduous. Petals as many as the 
sepals or more, conspicuous or minute, with a scale at the base of the blade. Stamens 
several to numerous. Akenes many, smooth, hairy or spiny; style minute or elongated. 
(Diminutive of L. rana==a frog; on account of the common wet habitat.) 
A. Plants aquatic or subaquatic; leaves divided into filiform segments when sub- 
merged. 
B. Petals much exceeding the sepals; carpels margined toward the base with con- 
spicuous tumid border. E. (RR. delphinifolius terrestris. ) 
R. delphinifolius Torr. (Swamp Buttercup) 
BB. Petals not much exceeding the sepals; carpels without distinct border. W. C. E. 
R. limosus.) R, purshii Rich. (Pursh Buttercup) 
AA. Plants terrestrial but often of very wet places; leaves never dissected into filiform 
segments (except JX. sceleratus). 
C. Leaves entire to crenate or dentate, not lobed nor more deeply separated into 
segments. 
D. Leaves ovate to cordate, coarsely crenulate or dentate. 
E. Leaves acute, dentate; mature akenes not veined on their faces. EF. 
R. gormani Gr. 
EE. Leaves rounded at apex, crenate; mature akenes striate-veined on the 
faces. W. E. R. cymbalaria Pursh (Seaside Buttercup) 
DD. Leaves either narrower or else merely crenulate or denticulate. 
F. Stem creeping, rooting from the joints. | 
G. Stem reclining or ascending, rooting at the lower joints only. W. C. E. 
(R. flammula unalaskensis; R. unalaskensis; R. michrolonchus; R. samoli- 
folius.) R. flammula L. (Smaller Spearwort) 
GG. Stem creeping, rooting at all joints. W.C. E. (R. reptans.) 
R. flammula reptans Schl. (Creeping Spearwort) 
FF. Siem erect, not rooting from the joints. 
H. Leaves oblong-lanceolate; petals 8—13 mm. long. E. (JR. bolanderi.) 
R. alismaefolius Gey. 

