46 ENGLISH BOTANY. 
SPECIES XVIIIL—RANUNCULUS ARVENSIS. Zinn. 
PuattE XXX VIII.* 
Reich. Ic. Fl. Germ. et Helv. Vol. III. Ran. Tab. XXI. Fig. 4614. 
No rootstock. Stem solitary, erect, slightly branched. Leaves 
stalked, the lowest ones obovate, toothed at the tip, the rest 3-cleft, 
or tripartite; or ternate, with 3-cleft or tripartite segments; the 
greatest amount of division in the leaves occurring in those on the 
middle portion of the stem, and the narrowest segments in those 
nearest its summit. Peduncles opposite the leaves and terminal, 
slightly hairy, not furrowed. Sepals slightly hairy, applied to the 
petals. Petals obovate-oblong, with a conspicuous scale over the 
nectary; scale broadest above, where it is truncate, as broad as 
the claw of the petal. Head of fruit spheroidal, much depressed. 
Achenes compressed, margined, covered with hooked spines or 
conical tubercles, distributed over the whole surface, but the mar- 
ginal ones the longest and stoutest; beak two-thirds the length of 
the rest of the carpel, with a narrowly triangular profile, straight 
or slightly arched. Receptacle hairy. 
In cornfields. Common in England; but only a straggler in 
Scotland, in which country the neighbourhood of Edinburgh and 
Glasgow appears to be the northern limit. 
England, [Scotland,] Ireland. Annual. Summer. 
Root fibrous, throwing up a single erect stem 6 inches to 2 feet 
high. Lower leaves wedge-shaped in outline, the upper ones with 
strap-shaped segments. Flowers scarcely } inch in diameter, pale 
yellow, more cup-shaped than usual in this genus. Achenes reddish 
brown, with a green beak; 4 to 8, usually all in one row, } to § inch 
long, sub-orbicular, with the two sides nearly parallel; the spines 
or tubercles varying considerably in size. In this species the 
processes on the carpels approach much nearer the margin than in 
R. hirsutus and R. parviflorus, for the margin itself seems to be 
carried up into a prominent ring from which the largest of the 
spines take their rise. 
A variety, inermis, is mentioned in the Continental Floras in 
which the achenes are destitute of spines or tubercles, the surface 
being merely reticulated; but this I have never seen, nor have I 
heard of its occurrence in Britain. 
Corn Crowfoot. 
* The Plate of R. arvensis is E. B. 135, with additional dissections drawn by 
Mr. J. E. Sowerby. 
