304 Botany. ; [ May, 
the pistil was withering away. The fact of self-fertilization in this 
plant seemed proved. Nature, however, does not disclose all her secrets 
on the first inspection, and a more careful study of this flower in all its 
stages will show that its wonderful machinery is contrived solely for 
securing cross-fertilization through the agency of insects, and that it 
cannot fertilize itself. In fact the anthers and stigma in any flower are 
never open at the same time. The mystery is explained when we ex- 
amine the flowers that have blossomed and are withering: the trap is 
open and the insects all flown. Each of the three constrictions, which 
were at first so narrow as only to admit of a small insect pushing its 
way between the hairs, is now gaping widely open, and all the bristles 
so wilted and flaccid as to offer no impediment to their escape. Now 
turning to a bud just bursting into flower, we find the bristles rigid and 
the trap set. The stigma is now widely open and ready to receive pol- 
len, but the anthers tightly closed and their pollen quite green. Each 
flower has then a double duty to perform: first, to catch insects which 
have been liberated by some flower previously in bloom, and to effect its 
fertilization with the pollen which they bring; second, to feed and hold - 
them there until its stigma has closed and its anthers burst. And, 
finally, it opens its trap and sends them forth with unimpaired vigor and 
a fresh load of pollen for the next. flower that blooms.” — (Kingston, 
Jamaica, February 28, 1877.) 
Pinus iris. — The attention of botanists living in the Middle States 
is directed to this tree, which has become rare in the North. As one of 
the most valuable of North American timber trees, attention has been 
drawn to this species as suitable for forest culture in many parts of the 
United States, and it is desirable to procure seed for this purpose from 
as far North as possible. According to the younger Michaux, Pinus 
mitis was found in his time in New York, Connecticut, and Western 
Massachusetts, and Mr. Lapham includes it in his catalogue of Wisconsin 
plants, but there is no evidence that this tree grows so far north at the 
present time. 
Botanists finding P. mitis*in the States above mentioned, or in Penn- 
sylvania, New Jersey, Ohio, or Michigan, are requested to communicate 
with the director of the Botanic Garden of Harvard University, Cam- 
bridge, Mass. — C. S. SARGENT. 
FLUORESCENCE OF CALYCANTHUS. — A decoction of the bark of the 
Calycanthus floridus, also known as “ sweet shrub,” is strongly fluorescent. 
My attention was recently drawn to this fact in examining a mixture of 
the bark in glycerine, which I had prepared in order to extract the 
pleasant odor of its essential oil. The vial containing the bark and glye- 
erine when looked at askance emits a rich, bluish shimmer. On com- 
paring a decoction of the bark of this shrub with that of the Æsculus, or 
buckeye, by concentrating the sun’s rays with a lens into a cone of light 
passing through the liquids, I discovered that the Calycanthus decoction 
