138 
RANUNCULUS 
Section V. BAFRACHLUM 
Batrachium DC. Syst. Nat. i, 233 (1818); [Gray Nat. Arr. Brit. PI. ii, 720 (1821) as a genus;] Rouy 
and Foucaud FI. France i, 58 (1893); \Ranunculoides Vaillant Bot. Paris 170 (1727)]. 
As is well known, the species of Ranunculus belonging to the section Batrachium are for the most part very variable. 
We do not think their polymorphism is very much more pronounced than in many other groups of plants, especially 
aquatic groups ; but the water-crowfoots are attractive plants and have for long received considerable attention. Hence their 
variability is better known than in some other groups. Much of the variability in Batrachium is due to habitat-conditions; 
and the undoubted influence of habitat factors induced some botanists of previous generations to regard all the members 
of the section Batrachium as a single species. Bentham (. Handbook p. 60), for example, reduced them all to “ Ranunculus 
aquaticus 1 Linn.,” and only recognised four varieties. Such synthetical treatment receives no support from the leading 
modern works on the flora of Europe. Recent botanists, in fact, appear to have arrived at comparative unanimity regarding 
the number of species of Batrachium. So far as British botanists are concerned, the modern views date back to Gray’s 
Nat. Arr. Brit. Plants ii, 720 (1821). Gray had seven species. Allowing for the fact that R. ho?no'iophyllus (= R. lenor- 
mandi) was not distinguished in Gray’s time, there is very little difference to be observed in the limitations of species by 
Gray (1821), Godron (1840), Syme (1863), Sir J. D. Hooker (1884), Rouy and Foucaud (1893), and the present work. Of 
botanists with markedly analytical tendencies, there have been Babington in this country and Boreau {FI. Centr. France ) 
in France. Babington {Manual ed. 9) made fifteen species : we have ten. 
We think those botanists are correct who regard the water-crowfoots as having descended from ordinary terrestrial 
or marsh buttercups ; and accordingly we place the section Batrachium at the end of the genus. The species belonging 
to the series Hederacei (see below) seem to be nearer the section Eu-Ranunculus than the series Aquatiles. On this 
view, the primitive Batrachian crowfoot was destitute of submerged leaves, and possessed a glabrous receptacle and glabrous 
achenes. R. tripartitus connects the series Hederacei with the series Aquatiles-, and R. tripartitus has often only cadu- 
cous or rudimentary submerged leaves, and its achenes are glabrous. The other species of the series Aquatiles with glabrous 
achenes {R. obtusiflorus , R. triphyllus , and R. fiuitans ) connect R. tripartitus with R. aquatilis and the closely allied 
R. trichophyllus. The most aberrant species are those which are destitute of floating leaves, namely, R. fluitans among 
the species with glabrous achenes and R. circinatus among those with hairy achenes. 
For characters of Batrachium, see page 125. 
Series of Batrachium 
Series i. Hederacei (see below). Submerged ( = lower filamentous) leaves absent. Receptacle 
glabrous. Achenes glabrous. 
Series ii. Aquatiles (p. 141). Submerged ( = lower filamentous) leaves present (but cf. R. 
tripartitus). Receptacle usually hairy (best judged when dry ; but cf. R. fluitans). Achenes glabrous 
or hairy. 
Series i. Hederacei 
Hederacei Rouy et Foucaud FI. France i, 59 (1893). 
For characters, see above. 
• Species of Hederacei 
1 5. R. hederaceus (see below). Lobes of the laminae broadest at the base. Flowers small, 
o'4 — ro cm, in diameter. Achenes straight on the inner margin. 
16. R. homoiophyllus (p. 139). Lobes of the laminae constricted at the base. Flowers larger*, 
ro — 1 - 6 cm. in diameter. Achenes convex on the inner margin. 
15. RANUNCULUS HEDERACEUS. Ivy-leaved Crowfoot. Plate 144 
R. hederaceus Johnson Kent 29 (1632); R. hederaceus aquaticus Parkinson Theatr. Bot. 1216 (1640); R. 
aquatilis hederaceus albus Ray Syn. ed. 3, 249 (1724). 
Ranunculus hederaceus L. Sp. PI. 556 (1753)!; Smith Ft. Brit. 595 (1800)!; Babington in Mag. 
Nat. Hist. ser. 2, xvi, 404(1855)!; Syme Eng. Bot. i, 29(1863) excl. syn. Gussone ; Willkomm et Lange Prodr. 
FI. Hisp. iii, 906 (1880); Rouy et Foucaud FI. France i, 59 (1893) excl. syn. Tenore p. 60 et syn. Gussone p. 60; 
R. hydrocharis form hederaefolius Hiern in Journ. Bot. ix, 67 ( 1 87 1 ) 3 ; Batrachium hederaceum Gray Nat. Arr. ii, 
721 (1821). 
1 We do not know whence Bentham got this name : we have not come across it in any of the works of Linnaeus. 
2 In comparing allied species, it is important only to compare analogous formae : the mud state of one species should 
not be compared with the deep water state of another. 
3 We cite Mr Hiern’s names as “forms,” just as he uses the word; but it must not be inferred that the term has 
the same significance as “ forma .” As a matter of fact, Mr Hiern’s “forms,” or “ultimate forms” as he terms them on 
p. 44 (1871), have no definite rank; and consequently it is incorrect to cite him as the sponsor when they are given the 
definite systematic grade of species, subspecies, race, variety, subvariety, or forma. 
