li>201 AGRICULTURAL BOTANY. 523 



(hiftiHl with a view of dotermining the carryiiijc Oiipaoity nf the range in that 

 sivtion and worldiig out a grazing: system adapted to conditions in tlie Great 

 Plains. 



Tlie vegetation in tlie area studied was found to be coniposetl of a large num- 

 ber of species, only a few of which produce a considerable amount of the total 

 forage. The dominating species were found to be Douteloua ffracilis and Stipa 

 comatn. The density of the vegetation was determined by the thickness of the 

 plants upon the ground surface and not by foliage growth. The total basal 

 cover of all species in the Mandan region was approximately GO per cent of the 

 ground surface, B. gracilis having n basal covering of about 20 per cent and 

 .S'. c'lninta nearly 10 per cent of the surface. Clipping data taken on different 

 day periods showed that Ti. gracilis produced 40 to .50 per cent and S. comata 

 from 15 to 20 per cent of the total forage. 



Upland societies of Pctoskey-Walloon Lake region, H. D. Clayherg {Bot. 

 Gnz., 69 {1920), No. 1, pp. 28-53, fig. i).— These notes, embodying the residts of 

 observations during some years, state that the sapling age In the area studied 

 shows the maxinuim increase in size for a given decrease in the number per unit 

 area, so that competition between trees of etiual age is keenest at this age. The 

 name syufolium is coined for the foliage layer, and the development and ecologi- 

 cal significance of this layer are analyzed. 



Throughout this region the response of the plant societies to interference and 

 changed environment has been adaptive, in so far as their constitution allowetl. 

 It is claimed that such natural societies as the blackberry are fitted to survive 

 in partly wild areas, while others can invade the fields in competition with the 

 crops. Characters favorable to survival are quick entry, speed of vertical 

 growth, quickness of fruiting after germination, quantity of seed production, and 

 efficiency of distribution. 



The phenological influence of the sea, O. Ritter (Bot. Centbl., Beilirfte, 36 

 (1919), 1. .'\ht.. No. 1, pp. 18-132). — An extended account is given of studies on 

 influences affecting plants as related to bodies of water, with a discussion of the 

 significance of the observations. 



Experimental cultures of garden salad plants in seashore situations, L. 

 Daniel {Compt. Rend. Acad. Sci. [/'ons], 168 (1919), No. 2, pp. 116-118).— A 

 study of salad plants grown on exposed seashores is said to have emphasized 

 the predominating part played by water in such situations. 



The effects of gases on plants, C. Wehmeu {Bcr. Dcut. Bot. Gc.sell., 35 

 (1917), Nos. 3, pp. 318-332, figs. J,; J,, pp. J,0.3-J,10, figs. 3).— Details are given of 

 studies regarding the effects of different gases on various trees and garden 

 plants. 



The influence of fluoriu on plants, A. Gautier and P. Clausmann (Compt. 

 Rend. Acad. Sci. [I'ari.^}, 168 (1919), No. 20, pp. 976-9.S2).— Details are given 

 of preliminary tests on 14 species in widely separated families in regard to the 

 presence and influence of fluorin compounds. 



The influence of the concentration of the nutritive medium on some 

 plants, L. GuRi.iTT (Bot. Centbl., Bcihrftc, 35 (1918), 1. Abt., No. 2. pp. 279-3/fl, 

 figs. 34). — Studies on nios.ses and higher plants are noted, with the effects of 

 different concentrations of nutritive media on their development. 



Effects of acids and the formation of soluble starches by mold fungi, F. 

 Boas (Bot. Centbl., Bcihcfte, 36 (1919), 1. Abt., No. 1, pp. 13.5-185, figs. 5).— 

 This is a detailed account of work which the author carried out during the 

 years 191.S-1917 with Aspergillus viger. 



A new fungus destroying complex polysaccharids, A. Epstein (Bui. .S'oc. 

 Bot. OenH-e, 2. ser., 11 (1919), No. 5-9, pp. 191-198).— The author obtained in 



9&46°— 20 3 



