424 Hill.—-The Genus Caltha in the Southern Hemisphere . 
marginal teeth of the lamina and appendages would serve to render such 
tiny air-chambers more efficient for the exclusion of water. 
Diels 1 has further investigated the New Zealand species C. novae - 
ze-landiae and some of the S. American species also. He points out that in 
C. andicola a few stomata occur on the morphologically lower side of both 
lamina and appendage, and that, as might be expected, there is a more or less 
normal development of spongy tissue. The majority of the stomata, how¬ 
ever, occur on the upper surface. 
In C. limbata , as he points out, the stomata have disappeared completely 
from the lower surfaces of both lamina and appendage, and the cell walls 
of the lower epidermis have become considerably thickened—a condition 
which obtains also in C. dioneaepolia —while in C. novae-zelandiae, in addi¬ 
tion to the thick-walled epidermis, the next layer of cells has also developed 
thick walls and forms a definite hypoderm which he regards as a special 
water-storing tissue. 
Mr. L. A. Boodle has very kindly examined the leaves of all the 
Ct -trf.Ji. Jut 
Fig. i.- C. limbata , Schlecht. Appendage in transverse section, u = upper 
surface; p — palisade; a = air-chamber below stoma. 
species and finds that in C. limbata, C. appendicalata, C. dioneaepolia , 
C. introloba , C. phylloptera , C. novae-zelandiae, and C. obtusa the stomata 
are confined to the upper surface of lamina and appendage, and that in all 
these species the lower epidermis consists of large thick-walled cells and is 
easily detachable from the rest of the leaf. 
In C. limbata , C. appendiculata , and C. novae-zelandiae , especially, the 
hypoderm cells on the lower side are conspicuously large and have thick 
walls like those of the epidermis. Both these layers of cells are devoid of 
chlorophyll and are more or less empty, and in all the species showing this 
thick-walled epidermis these two layers of cells may serve for water-storage, as 
Diels suggests. Inallthese cases normal lacunar spongy parenchyma is absent. 
1 Diels in Engl. Bot. Jahrb., vol. xxii, p. 260. See also Solereder, Sysb Anat. Dicot., vol. 1, 
p. 17 (Eng. trans.). 
