218 ECOLOGY, PLANT GEOGRAPHY [Bot. Absts., Vol. VI, 



1487. Guilliermond, A. Sur le chondriome et les formations ergastoplasmiques du sac 

 embryonnaire des Liliacees. [On the chondriosome and the ergastoplasmic formations of the 

 embryosac of lilies.] Compt. Rend. Acad. Sci. Paris 169: 300-303. 4 jig. 1919.— Author fig- 

 ures and describes the formation and nature of mitochondria, chondriosomes, and "ergasto- 

 plasmic" bodies in the embryo-sac of Lilium croceum and L. candidum. — V. H. Young. 



1488. Lillie, Frank Rattray. Problems of fertilization. 13X19 cm., xii + 278 p., 19 

 fig. Univ. Chicago Press: Chicago, 1919. — See Bot. Absts. 5, Entry 410. 



1489. Metz, Chas. W. Correspondence between chromosome number and Unkage groups 

 in Drosophila virilis. Science Si : 417-418. 1920.— See Bot. Absts. 5, Entry 1582. 



1490. Miller, E. C. Development of the pistillate spikelet and fertilization in Zea mays L. 

 Jour. Agric. Res. 18: 255-265. PL 19-32. 1919.— See Bot. Absts. 5, Entry 569. 



1491. Morgan, T. H. The physical basis of heredity. H X 21 cm., 300 p., 117 fig. J. B. 

 Lippincott Co. : Philadelphia, 1919.— See Bot. Absts. 5, Entry 422. 



1492. Morgan, T. H., and C. B. Bridges. Contributions to the genetics of Drosophila 

 melanogaster. I. The origin of gynandromorphs. Carnegie Inst. Washington Publ. 278. 



p., 4 pi., 10 fig. Washington, D. C. 1919.— See Bot. Absts. 5, Entry 424. 



1493. Nakahara, Waro. A study on the chromosomes in the spermatogenesis of the 

 stone-fly, Perla immarginata Say, with special reference to the question of synapsis. Jour. 

 Morphol. 32:509-529. 3 pi. 1919— See Bot. Absts., 5, Entry 429. 



1494. Schaffner, J. H. The expression of sexual dimorphism in heterosporous sporo- 

 phytes. Ohio Jour. Sci. 18: 101-125. 25 fig. 1918.— See Bot. Absts. 5, Entry 1627. 



1495. van Wisselingh, C. Uber Varibilitat und Erblichkeit. [Concerning variability 

 and heredity.] Zeitschr. indukt. Abstamm. Vererb. 22 : 65-126. 10 fig. 1920.— See Bot. 

 Absts. 5, Entry 1679. 



1496. Zelent, C. The method of procedure in the analysis of heredity. Sci. Monthly 

 11: 263-275. 1920. 



ECOLOGY AND PLANT GEOGRAPHY 



H. C. Cowles, Editor 

 Geo. D. Fuller, Assistant Editor 



GENERAL, FACTORS, MEASUREMENTS 



1497. Brenchley, Winifred E. Some factors in plant competition. Ann. Appl. Biol 

 6: 142-170. PI. 5, 10 fig. 1919.— The writer, at the Rothamsted Station, used barley and 

 mustard plants in a study of competition for food from the soil, for water, and for light. 

 When the food supply is limited, the amount of nitrogen was found to determine the amount of 

 growth, and the dry weight was found to be about the same per pot, regardless of the num- 

 ber of plants grown. — When there is competition for light in overcrowding, barley plants pro- 

 duced a smaller number of ears, an irregular number of tillers, a reduced amount of dry 

 matter, and a proportionately larger ratio of shoot growth as compared with root growth. 

 Crowded plants had a decreased power of utilizing the food supplied to the roots. Ade- 

 quately illuminated barley plants tended to grow toward a standard type of plant. With 

 crowding, this approximation to a standard disappeared. — G. R. Bisby. 



1498. Cribbs, James E. Ecology of Tilia americana. I. Comparative studies of the foliar 

 transpiring power. Bot. Gaz. 68:262-286. 13 fig. 1919.— In the dune region of Indiana 

 Tilia americana is found growing in a variety of habitats ranging from mesophytism to rather 



