11 
CRITICAL STUDY or RANUNCULUS AQUATILIS L. var. y. 
By Freperic N. WriixiaMs, F.L.S. 
Tue Batrachian Ranunculi, grouped together as a section of 
Ranunculus by De Candolle in Syst. Nat. i. 233 (1818), were raised 
to the ee of a genus by S. F. Gray in Nat. Arr. Brit. Pl. ii. 
720 (1821), but were still further reduced in grade to a subsection 
of the section Marsypadeniuwm by Prantl in Engler’s Jahrbuch, ix. 
266 (1887); which subordinate position, from the unsatisfactory 
nature of their defined specific characters, better befits the we ar 
ending a much desired mono. h of Ranunculus, the Batra 
chian group has stimoli the critical hae of many botanista, 
whose opinions have varied as much as the deviations from the 
type in the more Myra distributed (gacak: Several of the 
so-called species (as defined) appear to merge into each other; 
waters, in running streams, in shallow st the ge margins of 
lakes, in muddy ponds, ditches, the wet mud of river-banks, in 
marginal reaches, and quarry holes, their a variability, 
especially in leaf-form, is remarkable. the characters attri- 
buted to the species and their eabereinale forms, too much 
attention has been given to inconstant characters, of which some 
are variable, others valueless, and ose deceptive ; such especi- 
ally as the tapering of the cle, the relative length of petals, 
stamens, and styles, the contiguity or otherwise of the petals, the 
um stamens, the forms of the Zi pg tain poe and un- 
fertilized pistils, and especially upon the presence or absence of 
Ss leaves. Ina group of plants so sonnikiees to the modify- 
ing influence due to the varying sondlieos of their immediate 
environment, especially in so far affects their vegetative 
it i aps to 
species 
aaa t the same time serve to elucidate the natural affinities 
baiveen the different members of the group which their reticular 
bond of union so effectually obscures. With the character of the 
meth may also be associated that of the receptacle to which they 
are laterally attached, whether ome or ovate-conical in form, 
an 
forms under these two genera. Unless the sage affinities 
are clearly marked off from intra-specific variation by characters — 
more definite than those of leaf-modification, which are mainly if 
not entirely due to the chemical composition, temperature, depth, 
tahiegrse of the water in which they grow, the study of the 
orms of the water crowfoots will render the attempts 
$5 ites Fok mn salinlaetolley as nugatory and ineffectual as in the 
