826 EXPERIMENT STATION EECOBD. 



one or both cotyledons of crucilerous fceedling.s 10 days old. The resulting anoru- 

 alies of development, external and internal, are described. 



Injury to vegetation by coal tar and other vapors and protection there- 

 from, R. EwKHT (Ztschr. Pflanzenkranlc, 2Jt (,lDVt), Nos. 3, pp. 257-273; 6, pp. 

 S21-3JiO, fiys. l.'f). — The author gives a detailed account of the injury to vege- 

 tation due to the deposit and absorption of air-borne products from chemical 

 works of various kinds at several points in Germany, with lists of plants found 

 to be susceptible or resistant to these substances. 



These effects, although not entirely uniform, are said to be easily distinguished 

 by both external and internal indications from injury by smoke-borne products. 

 A peculiar lacquered appearance was produced on the upper surface of the 

 leaves of a number of economic plants, also frequently a rolling and crinkling 

 of the laminae. Some showed discoloration over part or all of the surface, 

 accompanied by the formation of a superficial cork layer. Fruit trees showed 

 a decrease of product, and vegetables from this neighborhood (usually within 

 1,000 meters) quickly lost their turgor and fresh appearance when gathered 

 for market. The production of these effects varied somewhat with the wind 

 and precipitation or differences in the materials discharged. 



Experiments under controlled conditions during three years, and in part 

 already confirmed by those of 1914, gave generally similar results which are 

 detailed. It appears that the degree of injury depends not alone upon the 

 amount of materials present in the atmosphere but also upon heat or insola- 

 tion and dryness. The lacquered appearance followed exposure after one or 

 two days, and it was here also confined to the upper leaf surface. Spraying 

 with water before exposure to the emanations did not protect the plants from 

 injury. Blooms of fruit trees were injured by the presence of the products. 

 Spraying with Bordeaux mixture of 0.5 per cent strength appeared more harm- 

 ful than otherwise, a result contrasted with that previously noted under other 

 conditions (E. S. R., 28, p. 2-17). The glossy appearance of the upper leaf sur- 

 face seems to be at least partly due to the drying out, thinning, and flattening 

 of the epidermal cells. In some cases a superficial cork layer was formed. 



The precise chemical and physical action of these emanations is not yet 

 settled. Interference with the protective functions of the epidermis is a probable 

 element, as plants sufter more in dry and sunny weather, with a degree of re- 

 covery in shade and moisture which appears, however, to be greater than it 

 really proves to be in the end. 



Studies on smoke injury to vegetation in Ratibor-Plania, R. Otto (Ber. K. 

 Lehranst. Ohst u. Gartenhau rroskau, 1913, pp. 116-118).— This is a brief 

 discussion of the studies noted above. 



The pathological action of tar on plants, F. von Gabnay (Centbl. Gesam. 

 Forstio., 39 {1913), No. 11, pp. Jf97-504). — The author gives a brief account of 

 injury to ti'ees by tar used on the trunks ns protection against the ascent of 

 caterpillars. It is said to have involved not only the cambium but also the 

 sap wood, extending also beyond the edges of the tarred area. This injury is 

 ascribed largely to the exclusion of air, but partly also (as in case of injury 

 to roots of trees standing near streets paved with wood blocks) to the action of 

 salts and acids. Reports and views of other observers are also discussed. 



The vegetation of south Florida, J. W. Harshbekger (Trans. Wagner Free 

 Dist. ScL Phila., 7 {19U), pt. 3, pp. 189, pis. 11, figs. 2).— This is a monograph 

 on the vegetation of Florida south of 27° 30' N. (exclusive of the Keys), dealing 

 with the geography, physiography, geology, and phytogeography of this region, 

 giving lists of plants as found in the various associations or formations, and 

 concluding with a floristic and ecologic analysis of the region and a discussion 

 of the evolution of each of the formations noted. 



