1914] CURRENT LITERATURE 341 
Anatomy and plant hybrids.— Miss HoLtpEn” has suggested that anatomical 
structures may be used in the recognition of spontaneous hybrids which are 
identical in external appearance with ordinary species. There can be no ques- 
tion but that spontaneous hybrids are of extremely common occurrence, and 
when they are recognized at all, they are described as variations of recognized 
species. She uses as illustration a case of identical external structure covering 
profound differences in internal organization. A hybrid between Betula 
pumila and B. lenta was recognized by anatomical structure which otherwise 
appeared to be B. pumila. Another illustration is obtained from a form of 
Equisetum which was clearly proved to be a hybrid. If this weapon proves 
0 be as efficient as Miss HoLpEN hopes, it will go far toward attacking suc- 
cessfully the problem of mutations.—J. C 
An Arkansas prairie.—As a result of a tour of a portion of Eastern Arkan- 
sas, HARPER” gives us some notes upon the phytogeography of the region, the 
most interesting of which concern an area of natural prairie, known as Grand 
Prairie, in Prairie County. The plant list, made about the middle of June, 
shows a very rich flora, estimated at 150 species, in which the Compositae, 
osae, and Juncaceae are well represented. No solution is offered of 
the problem of the occurrence of a prairie in this old flood plain other than 
indications that the soil moisture shows great extremes when spring and mid- 
Summer conditions are contrasted. The study of such areas in Arkansas seems 
to have been neglected and to offer excellent opportunities for botanical 
investigation.—G. D. FULLER 
The vegetation of the Hempstead Plains—R. M. Harper presents the 
interesting floral features of the Hempstead Plains, which are situated in the 
western part of Long Island, New York.?3 In this area there is a natural 
Prairie of some 5° square miles in extent, stag of which shows vegetation 
_ €ssentially undisturbed by human influences. The commonest herb is Andro- 
pogon Scoparius, which also is common on many western prairies. HARPER 
usses the possible causes of such a prairie, without coming to definite con- 
clusions, except that climatic theories are ruled out, as is the influence of fire 
or of grazing. It is more likely, he thinks, that the Hempstead prairie is asso- 
ciated with some peculiar type of soil—H. C. Cow 
VPs 
Ses * HoLpen, Ruta, Anatomy as a means of diagnosis of spont plant hybrids, 
ence N.S. 38:32, 933. 1913. 
* Harper, R. Se notes on the coastal plain of Arkansas. 
Plant World + 7: rae 
* Harper, R. M., The Hempstead Plains; a natural prairie on Long Island. 
a - Geog. Soc. 43: 351-360. figs. 5. 1911; also Torreya 12:277-286. figs. 7. 
2 
