302 BOTANICAL GAZETTE [NOVEMBER 
The rings can be seen more clearly by looking across the figure 
from nearly the level of the paper. The negative was made twice 
the size of the section, and the illustration reduced to natural size. 
The same sections without reduction are shown in fig. 15. The 
appearance, under a low magnification, is shown in fig. 16, which 
includes six of the growth rings. The rings are not at all con- 
spicuous, and the number of rings probably could not be counted in 
the illustration. Even with the position on the rings marked with 
the numerals 1-6, they are not easily identified. Two structural 
features cause a ring. At the close of the growing: period a few 
Fic. 15.—Aloe ferox: from same negative as fig. 14; X2 
smaller bundles at irregular intervals are probably responsible, but 
the principal cause is that the parenchyma cells formed at the close 
of a growing period are slightly smaller and have slightly thicker 
walls. 
I wrote to Professor SCHONLAND, Director of the Albany Museum 
at Grahamstown, South Africa, and to Mr. E. E. Garry, formerly 
of Queenstown but now of Naboomspruit, Transvaal, South Africa, 
inquiring about climatic conditions in the localities from which 
the material was secured. Professor SCHONLAND, to whom I 
am also indebted for material of Aloe ferox, wrote as follows: 
here are two maxima of rainfall, in October and November, and in 
March and April; but this comes out only when the averages of a number of 
years are worked out and give a wrong picture of the relation of the flora to 
our rainfall. It is true that the winter, from the middle of June to the middle 
of September, is generally dry; but I have known good rains in these three 
months. Last year (1920) the October-November rains failed us; we had 
