1922] CURRENT LITERATURE 245 
infection. Hybrids havi i ts show in many instances 
promising resistance. The Buco, representing as it does some forty 
diseases and pests in the Philippines and nearly an equal number in the Asiatic 
countries visited, emphasizes the need for intensive studies of plant diseases in 
the regions where they have been long established.—W. T. SwINGLE 
Stelar morphology,—In his presidential address to the Royal Society of 
Edinburgh, BowERr” emphasizes the importance of the principle of similitude 
(GALILEO) in the investigation of the stelar morphology of the higher plants. 
He argues that, inasmuch as the surface of an organ or tissue varies only as 
the square of its linear dimensions, but the bulk as the cube, the larger a plant is 
the more dependent it will be upon its form and detailed structure, not only for 
its stability, but also for the performance of its functions of absorption and 
transit of liquids and gases. This will apply not only to the external surface, 
but also to those internal surfaces which limit one tissue tract from another. 
Upon the basis of this premise, he concludes that in the ontogeny and phylogeny 
of ferns the form of the vascular tissues is largely dependent upon the size of 
the plant and of its various organs. Thus, as the fern plant and its foliar 
appendages become larger, the simple and presumably primitive protostele 
tends to become involuted, medullated NE or dissected into separate 
strands (polycycly, eae hophcae! ely). 
OWER’S correlations between size, form, and function are very suggestive, 
and deserve careful ae. particularly by students of the phylogeny 
of the vascular cryptogams. It must be admitted, however, that there is a 
considerable element of uncertainty in interpreting such correlations. The 
fact that complex structures tend to occur in large plants does not prove neces- 
sarily that size is the primary factor in their evolution, although such a con- 
clusion appears to be extremely plausible-—I. W. BAILEY. 
Deccan vegetation.—The ecological problems of many portions of India 
are complicated by the density of the population and the intensity of the 
grazing. The rainfall of 27 inches in the Deccan coming during the months 
from June to October, preceded by a very hot and dry period, causes the 
erosion of fields denuded of vegetation by drought and grazing. In such a 
region the study of natural vegetation in areas protected from cattle has been 
begun by Burns and CHAKRADEV" as a preliminary to.work on the improve- 
ment of grazing lands. Permanent quadrats were established within barbed 
wire inclosures. Native grasses such as Andropogon monticola and Iseilema 
laxum appear to be able to establish themselves completely, and it seems 
* Bower, F. O., Size, a neglected factor in stelar morphology. Proc. Roy. 
Soc. oe 4131-25. 1921 
™ Burns, W., and Geena ae: G. M., An ecological study of Deccan grassland. 
Jour. Indian Bot. 2: 84-01. 1921. 
