The Genus Caltha in the Southern Hemisphere, 
BY 
ARTHUR W. HILL, M.A., 
Assistant Director , Royal Botanic Gardens, Kew. 
With ten Figures in the Text. 
T HE genus Caltha , L., was subdivided by de Candolle (Syst., i, p. 307 , 
1818 ) into two sections, Psychrophila 1 and Populago , the distinguishing 
feature being that in the former the calyx is persistent, while in the latter 
it is deciduous. Under the section Psychrophila he placed two species, 
C. appendiculata , Pers., and C. sagittata, Cav., both from Antarctic South 
America, while the other section included all the Northern Hemisphere 
species. 
It is only with the Southern Hemisphere species that we are concerned 
in the present paper, and it will be shown that the peculiar foliage characters 
in these species—which extend from the high Andes of Ecuador to the 
Falkland Islands, Tasmania, Victoria, and New Zealand—-mark them off as 
a peculiar and remarkable section of the genus more obviously than does the 
floral character originally noticed by de Candolle. 
Berchtold and Presl (Rostl. i. Ranunc,,p. 80 , 1823 ) raised de Candolle’s 
section Psychrophila to generic rank, which both Gay (FI. Chil., i, p/ 47 ) and 
Asa Gray 2 also adopted. Gay gives descriptions of four species, the 
two additional ones being P.andicola (1. c., p. 49 ), and Hooker’s Caltha 
dioneaefolia , described in the London Journal of Botany, vol. ii, p. 306 (Gay, 
1 . c., p. 51 ). 
The general floral similarity of the Calthas from the Southern and 
Northern Hemispheres is so close that the establishment of a separate genus 
for the Southern forms would prove misleading, and Gay has not been 
1 The name is derived from pvxpos, cold, and piXeoj. 
2 The following note on the genus Psychrophila is given by Asa Gray in Botany U.S. Expl. 
Expedition, i,p. 13:— Psychrophila'. ‘Distinguished from Caltha as a genus by the membranaceous 
appendages which terminate the thickish sepals, either attenuated and as it were caudate, as in 
P. appendiculata , or short and blunt, as in P. dioneaefolia ; by the few stamens (from 5 to 9) ; and the 
few (2 to 9) and 2-8 -ovtilate ovaries , and 2-3 -seeded follicles ; the subdioecious flowers; and the very 
different habit. It must be confessed, however, that the New Zealand species of Caltha , recently 
illustrated by Dr. Hooker, having narrow and attenuated sepals, is too nearly intermediate for the 
satisfactory discrimination of the two genera.’ In the Genera Plantarum, i, p. 6, Psychrophila is 
maintained as a section of Caltha. 
Psychrophila , Rafin., Atl.Journ. (1832), p. 144, refers to a Caltha from Oregon, and his two 
specific names P. auriculata and P. sagittata are not synonymous with Caltha sagittata , Cav., as the 
Index Kewensis states, apparently following Torrey in Ann. Lyc. Nat. Hist., New York, ii, p. 164. 
Rafinesque’s plant appears to be Caltha leptosepala , DC. 
[Annals of Botany, Vol. XXXII. No. CXXVII. July, 1918.] 
