428 BOTANICAL GAZETTE [DECEMBER 
of his results is as follows: the stem is monostelic, and one leaf trace 
passes to each leaf; the stele contains no pith, and is of several types,(1) a 
xylem mass with internal protoxylem, connected with leaf traces, (2) a xylem 
mass with indefinite scattered protoxylem, (3) a xylem mass with peripheral 
protoxylem, (4) sub-coilateral,(5) a collateral bundle. The author thinks 
that the sub-collateral structure has probably been derived from a more 
complicated type by reduction, and that the filmy habit of Hymenophyllum 
is probably not primitive.—J. M. C 
Mr. R. F. SHOVE has published an account of the structure of the 
stem of Angiopteris evecta, which in 1864 had been described in detail by 
Mettenius, but from whom the present author differs in several particulars. 
The position of the protophloem in the stem stele is said to be anomalous, 
occurring on the outer side of the stele in the form of a discontinuous arc. 
The centrifugal growth of the phloem is also said to be contrary to that 
described for most other ferns, but the other Marattiacez are not included 
in this comparison. The mesarch and endarch structure of the steles was 
confirmed, and also the presence of several initials at the apex of the stem. — 
pm, C 
W. L. Bray discusses the relations of the North American flora to that 
of South America. Few new conclusions are reached, but there is an 
interesting summary of the known data on the subject. The most impor- 
tant agencies which have brought about relationships are those which have 
acted in the past; the endemic northern floras of Mexico and the Andes 
are to be referred to such causes. Minor agencies of distribution are still 
active, especially those along the gulf zone and those due to man.—H. C 
COWLES. 
ULE DESCRIBES several isolated observations” that he has made concern- 
ing the influence of animals upon plants in the tropics. These observations 
have to do mainly with pollination and seed dispersal. He opposes the view 
that palms and other plants which develop a considerable amount of heat in the 
_ flowers do so with any relation to pollination. This theory is a prior? improb- 
able, and the author adds that no protection would be necessary to the insects 
in tropical climates, and furthermore that the insects do not fly at night.— 
H. C. COWLES. 
Miss ETHEL N. Tuomas has announced” the discovery of double fer- 
tilization in Caltha palustris. The original discoveries of this phenomenon, 
it will be remembered, were among the Liliacez, so that the discovery of 
** Annals of Botany 14: 497-525. pls. 28-29. 1900. 
9 Science 12: 709-716. 1900. 2° Ber. deutsch. Bot. Ges. 18 : 122-130. 1900. 
** Annals of Botany 14: 527-535. pi. 30. 1900. 
