428 EXPERIMENT STATION EECOED. 



woody plant tissues is related to liydrolyzing agents of bacterial origin. No 

 evidence of petrifaction was noted. 



The relative action of cold on herbaceous plants, W. Russell (Bui. Soc. 

 Bot. France, 61 {1914), No. IS, pp. 113-118, figs. 1). — Observations are given 

 on the effect of freezing on herbaceous and semiherbaceous plants in the vicinity 

 of Paris during the winter of 1913-14. This winter is said to have been espe- 

 cially severe, and wbile perennial plants were not seriously affected, herba- 

 ceous ones whose growth had been prolonged late into the fall were destroyed. 



The author found that ice formed within plant tissues caused modifications de- 

 pendent upon the form of the cells. Where the ice occurred in superficial cells, 

 but little injury resulted, but where it was formed deep within the tissues, espe- 

 cially within the vessels and parenchyma surrounding them, the death of the 

 plant usually followed. It was also found that certain cells could continue 

 living for a time although the rest of the plant was killed, and that there could 

 be temporary growth of organs although the members on which they depended 

 were dead. 



Further studies of the effects of smoke from towns upon vegetation in 

 the surrounding areas, C. Crowther and D. W. Steuart (Jour. Agr. 8ci. 

 [England'], 6 (1914), No. 4, pp. 395-405). — The authors have extended the 

 studies previously noted (E. S. R., 33, p. 126) by making attempts to measure 

 directly the effects of atmospheric pollution upon trees and upon crops grown 

 on agricultural land near the city of Leeds, and they give some details thereof, 

 with the general effects of air-borne impurities. 



In case of trees, individual buds may be injured so that they open late, if at 

 all. Leaves are injured at any stage, but particularly when young, and if they 

 are injured for several successive seasons the tree becomes sickly and gradually 

 dies away, the forms of progi'essive injury being described. Conifers are more 

 susceptible than deciduous trees, and both are more so than are most farm crops. 



As regards cultivated crops, heavier tillage is required in the smoky district. 

 Hedges also are injured and wire fences, metallic roofing, etc., are less durable. 

 The finer and more valuable grasses tend to die out. Young leaves of cereals 

 may redden or bleach at the points, the shoots are thinner, the crops are more 

 uneven in ripening, and the grain is impaired as to appearance, quality, and 

 market value. 



The detrimental action of smoke, etc., is at its height in damp weather under 

 conditions favoring accumulation of smoke gases over the growing crops. Quick- 

 growing plants with thick leaves best resist the influence of the smoke. Fruits 

 do not bear well or thrive. Some late vegetables suffer more than early ones. 

 With a few exceptions noted, ornamental flowers die out or fail to do well in 

 this region. 



The seed coat of clover, V. Fominykh (Zhur. Opytn. Agron. (Russ. Jour. 

 Expt. Landw.), 15 (1914), No. 4, pp. 294-316, figs. 15).— A study of the seed 

 coats of red clover has led to the conclusion that a thick seed coat is not char- 

 acteristic of sound and full seeds, but that this character diminishes germi- 

 nability. A glossy seed coat is an indication of sound and full seed, but this 

 appearance may be impaired or lost by injury in threshing. Ripeness of seed 

 is indicated by a violet or dark blue-green color, which is lost, however, in 

 unfavorable situations, such as excessive moisture. A gray-brown color and 

 shriveling of the seed coats show correlation with quick germination, but not 

 necessarily with high quality of stock. 



On the origin of cultivated rice, A. Chevalier and O. Rcehrich (Compt. 

 Rend. Acad. Sd. [Paris], 159 (1914), No. 14, pp. 560-562) .—The authors have 

 made a study of rice plants growing in Asia and Africa, comparing the species 



