Floristik, Geographie, Systematik etc. 329 



scribed with special reference to the correlation between forests 

 and soils and the relative abundance and distribution of the various 

 species. Pinus rigida is the most abundant tree in the State while 

 Quercus alba is the most generally distributed. 



W. B. McDougall. 



Hartwell, B. L. and S. C. Dämon. The influence of crop 

 plants on those which follow. 1. (Rhode Island State Col- 

 lege Agr. Exp, Bull. 175. f. 1. June 1918.) 



The general plan of the work as stated by the authors is to 

 grow sixteen different crops on that number of plats for two sea- 

 sons prior to growing a different one of the crops over the entire 

 area every third year. The results for ten years are reported, 

 onions having occupied the entire area the third year, buckwheat 

 the sixth year and alsike clover the ninth and tenth years. Onions 

 grew best after redtop and poorest after mangel beets. Buckwheat 

 produced the most grain after rutabaga turnips and the most straw 

 after hubbard squashes. It produced the least grain after millet and 

 after timothy, and the least straw after timothy. Alsike clover grew 

 best after redtop and poorest after alsike clover. 



W. B. McDougall. 



Hayden. A., The ecologic foliar anatomy of some plants 

 of a prairie province in central Iowa. (Amer. Journ. Bot. 

 VI. p. 69-85. 6 Pls. Feb. 1919.) 



The leaves of twelve upland species and sixteen alluvial basin 

 species are described and figured on the plates. The descriptions 

 are made concise and uniform, each description consisting of five 

 parts with the following headings: habitat; orientation and arrange- 

 ment; gross structure; histology; summary. W. B. McDougall. 



House, H. D., ThevegetationoftheeasternendofOneida 

 Lake. (New York State Mus. Bull. N° 197. p. 61—71. f. 4—12. 

 May 1917.) 



An introduction including remarks on the geology and climatic 

 influences of the region is followed by an analysis of the Vegetation 

 under the following headings: forests; austral elements of the Vege- 

 tation; shore Vegetation; lake Vegetation; stream Vegetation; marsh 

 meadow Vegetation; sandy fields. W. B. McDougall. 



Hutchinson, A. H., Limiting factors in relation to specific 

 ranges of tolerance of forest trees. (Bot. Gaz. LXVI. p. 465 — 

 493. f. 1—7. Dec. 1918.) 



The paper is based on extensive studies of forests throughout 

 the Province of Ontario. Maps are presented to show the impossi- 

 bility of accounting for the distribution of many tree species on the 

 basis of temperature or water alone as limiting factors and the con- 

 clusion is reached that the relative development of the soil, "parti- 

 cularly with reference to its humus content, may act as a limiting 

 factor regionally as well as locally." The element of time as a fac- 

 tor is also considered of great importance. The deciduous hardwood 

 forest is encroaching upon the coniferous forest region in northern 



