Arctic Plants: Morphology and Synonymy 



27 B 



merely reniform; on the other hand some very tall specimens collected near 

 Peace river landing, Athabaska, by James M. Macoun, show the leaf-margin 

 very finely crenulate and the outline roundish reniform with the sinus relatively 

 narrow. 



With regard to the arctic plant, typical Caltha palustris occurs in Nova 

 Zembla from where it is reported by Kjellman and Lundstrom ^ and where I 

 found it myself;^ my specimens, however, are very small, measuring only from 

 5 to 7 cm. The forma radicans, on the other hand, is known from arctic Scandin- 

 avia, as stated above, and Kjellman found it also on the Asiatic coast of Bering 

 strait, besides on St. Lawrence island. Furthermore, all the specimens collected 

 on the Canadian arctic expedition represent this form (Fig. G: 1-2); and it is 

 known also from the islands in Bering sea. 



The Siberian plant, on the other hand, represents mostly the variety 

 sibirica Regel, with the forma radicans Kegel, characteristic of which is that 

 the lobes of the leaf -blade form a very narrow sinus (Fig. 3). 



FlGtTEE G. 



1. Caltha Tpalustris L. forma radicans (Forst.) Hartm. A fruiting specimen from Hersohel island 

 showiug three rooting shoots; two-thirds of the natural size. 2. A basal leaf of same form 

 from the same locality ; two-thirds of the natural size. 3. A leaf of C. palustris L. var. 

 sibirica Regel forma radicans CForst.) Reg. from Jakutsk, Siberia; two-thirds of the natural 



In comparing the leaf-outline of these various specimens we notice that the 

 leaf of the typical plant in Europe is mostly reniform with the margin crenulate, 

 but varying to almost roundish, suborbicular; on the American continent the 

 typical plant has the leaf -blade more or less reniform but, as stated above, the 

 orbicular outline does also occur; the margin varies from crenulate to entire; 

 the latter form is evidently C. integerrima Pursh. In Siberia the leaf-outline is 

 generally roundish-reniform with the sinus narrow, a leaf-type that recurs in 

 the Siberian forma radicans. In other words, the form of which the stems are 

 decumbent and rooting occurs throughout the northern hemisphere, and the 



1 Fanerogamer frILn Novaja Zemlja, etc. 



2 Dijmphna Expedition (I.e.) 



(I.e. p. 310.) 



