157 
Herbarium ; the var. Howe//iz is based on the plant distributed 
by Mr. Howell as C. dzflora, DC., but Dr. Huth doubts if it is 
_ the Candollean species; it is the same as Bridges’ No. 2 from 
California. The plant collected by the Wilkes Exploring Ex- 
pedition in Washington Territory, distributed as C. dzffora, DC. is 
different. C. palustris, var. flabellifolia, which isattributed to Pursh, 
was described by Pursh as a species, and I have maintained that it 
should be so regarded (Trans. N, Y. Acad. Sci. ix. 5, 6); C. 
dentata, Muhl., is quoted as a synonym of this and if they are the 
same is the older name. C. fa/ustris, var. arctica, Huth. (C. 
arctica, R.Br., is, according to the specimen preserved at the 
British Museum of Natural History, apparently C. nadans, Pall., 
which species Dr. Huth does not attribute to America, although 
it has been found as far south as Minnesota by Be J. A 
(BULLETIN, xvii. 99). C. palustris, var. parnasstifolia, Huth (C. 
parnassitfolia, Raf.) is said, following DeCandolle, to occur in New 
Jersey and Carolina, and var. asarifolia, Huth (C. asarifolia, DC.) 
to occur in Alaska, following the same author; Dr. Huth does 
not appear to have seen specimens of either of these. 
N. L. B. 
In the Botanisches Centralblatt, No. 6, of 1892, is a brief re- 
view of an article by Gregor Kraus, on calcium oxalate in the bark 
of trees. The author attempts to answer the question, Are the 
crystals of calcium oxalate in the bark of trees afterward dis- 
solved and used in the plant economy, and therefore to be con- 
sidered reserve material rather than excretory matter ? To an- 
Swer this question, he made exact determinations of the variation 
in quantity of this material at various seasons of the year. 
A number of examples are given showing that the amount 
contained in winter was greatly diminished after the spring growth 
had commenced, Examples of this are twigs of Rzbes sanguin- 
eum, which were found to have lost sixteen per cent. of the 
crystals from the 16th of December till the 27th of April. Kosa 
Canina between the 1 7th of March and the 5th of May lost a little 
over twenty-eight per cent. Pyrus Malus from the 3rd of April 
to the 5th of May lost fifty per cent. 
These experiments were not confined to one period of growth, 
but were repeated for several successive seasons. The author 
