1^ Note and Comment. 
Wanted. — Short notes of interest to the general botan- 
ist are always in demand for this department. Our read- 
ers are invited to make this the place of publication for their 
botanical notes. It should be noted that the magazine is 
issued as soon as possible after the fifteenth of each month. 
Tropical Trees. — "In an ordinary temperate forest," 
writes Dr. Francis Ramaley in Popular Science Monthly, 
"the number of species of trees can almost be counted on the 
fingers of two hands. The species in a Northern coniferous 
forest might be counted on the fingers of a sinp-le hand. In 
a West Java forest there may easily be fifty species of trees 
within a distance of as many feet from an observer. In the 
whole island of Java there are probably a thousand dififer- 
ent kinds of arborescent plants — perhaps more." 
Sphagnum and Lime.— The peat moss (Sphagnum) 
is so abundant in many parts of the world that it fills im- 
mense bogs, and its dead stems, mingled wnth other vege- 
table debris, form layers of peat many feet in thickness. In 
other parts of the world, however, the peat mosses are un- 
accountably absent, and it has been conjectured by botanists 
that their absence is due to large amounts of lime or other 
mineral salts in the water. This has been tested by E. N. 
Transeau, who finds that f>eat mosses, contrary to the gen- 
eral impression, are not prevented fn^m growing by such 
mineral salts. 
The W.\ter-Cress CiENrs.—There are people who 
tliink tliat the water-cresses are still to be found in the genus 
y .istitrnuut. but f(.)r some years they have Ijeen masquerad- 
ing under the name Roripa.. This latter name was given 
to the plants in 1760 and quite forgotten until a botanist 
