298 BOTANICAL GAZETTE [APRIL 
“normal rosy or slightly bluish-red tint,” when exposed to carbon dioxide, 
and becomes “ yellow with a tinge of brown ;”’ and ‘‘in the presence of nas- 
cent oxygen the light red hue deepens momentarily and ends by becoming 
a very deep blood red.” In a properly guarded test tube a solution of haema- 
toxylin-is placed which has been acidified with carbon dioxide. Into the 
brownish-yellow liquid living diatoms are placed and exposed to bright light. 
Gas arises, and within fifteen minutes the color has become quite red, con- 
tinuing to deepen in color until it is blood red. By using two tubes filled 
with normal reddish solution of haematoxylin, and placing a living snail in 
one and diatoms in the other, the former pales rapidly under the influence of 
the carbon dioxide from the snail, while the latter rapidly darkens and red- 
dens. In all cases, of course, other tubes containing the solution are used as 
checks.— J. M. C. 
Dr. ANTON HANseirG‘ has recently investigated the ability of plolen to 
resist water, and the relation between this power and the protection against 
rain and dew. Since many plants whose pollen grains and sporophylls are 
fully protected against rain and dew have very resistant pollen, and, on the 
other hand, plants with exposed sporophylls often have pollen very sensitive 
to moisture, he considers Lidforss’ parallelism between protection against 
rain and the resistance power as questionable. Although the cohering pollen 
of many plants needs protection against too early wetting, there are many 
entomophilous plants whose pollen can withstand wetting without injury. In 
different families and genera there are many intermediate forms between 
these and those with pollen very sensitive to moisture. The author gives 2 
long list of plants whose pollen germinates well in pure water, but whose 
sporophylls are not protected against wetting. Another list includes those 
whose sporophylls are protected against wetting, but whose pollen germi- 
nates thoroughly in pure water. Plants whose pollen germinates poorly oF 
not at all in pure water will be noted later, the present paper being a prelim- 
— statement.—C. J. ie 
J. M. JANSE has —— recently an account of his os upon root 
sndonl nytes7 Hee on monocot 
to 
