246 BOTANICAL GAZETTE [MARCH 
possible that a more mesophytic grassland may be the climax, with the forma- 
tion of a turf resisting erosion 
Investigations by Burn during one of the worst droughts on record, in 
1918-19, have taken into account some of the plants showing the most successful 
resistance to such arid conditions. Such data not only add to our knowledge 
of the existing vegetation, but furnish material for improving existing economic 
conditions in a region where grazing is of first importance. 
e anatomy of many plants of the arid region is also being investigated 
y SABNIS.3 The results of such efforts are certain to be valuable for India 
and interesting to botanists elsewhere.—G. D. FULLER 
Tension zone between forest and prairie.—Following an earlier study by 
WEAVER and TuIet, an interesting tension zone investigation has been carried 
on by Poor, WEAVER, and JEAN“ in eastern Nebraska. Stations were selected 
at Peru, near the Missouri River, and at Lincoln, sixty miles west of Peru. By 
means of quantitative experimental study, striking contrasts between these 
two stations, due to both climatic and edaphic factors, were brought to light. 
The prairies and woodlands near Lincoln are much more xerophytic than 
those near Peru, in spite of the short distances involved between the two 
places. Available soil moisture during the summer of 1917 was exhausted 
on eighteen different days on a Lincoln prairie and on only four different days 
on a comparable Peru prairie. Many mesophytic woodland species pass out in 
traversing the area between these two places. The high saturation deficit 
and the low soil moisture content of the prairie sites in eastern Nebraska 
constitute barriers over which forest trees can scarcely pass. The authors 
feel that herein is the most ready explanation for the confinement of Nebraska 
woodlands to the moist slopes of narrow valleys and for the general treelessness 
of prairies. In the order of increasing mesophytism, the forests about Peru 
are as follows: bur oak-yellow oak, black oak-hickory, red oak, linden-ironwood, 
while the common forest type about Lincoln is that of the bur oak-hickory.— 
H. C. Cowles. 
Composition of plants as affected by nutritive elements.—Growing the 
oat plant in analyzed quartz sand, Dickson's has made a study of the effects 
of a deficiency of certain nutrient elements on the calcium and phosphorus 
% Bune, R. K., Drought resisting plants in the Deccan. Jour. Indian Bot. 2+ 
27-43. 1921. 
3 SaBnis, T. S., The aia a anatomy of the plants of the Indian desert. 
Jour. Indian Bot. 2:1-19, 61-79, 93-1 1921 
™4 PooL, R. J., WEAVER, J. E., on ee AN, 'F, C., Further studies in the ecotone 
between prairie and woodland. Univ. Nebraska Studies 18:1-47. figs. 17. 1918. 
8 DIcKSON, J. G., The relation of certain nutritive elements to the composition of 
the oat plant. Amer. Jour. Bot. 8:256-274. figs. 2. 1921 
