92 GENETICS [Bot. Absts., Vol. VI, 



658. Cook, O. F. Cotton a community crop. Jour. Heredity 11: 174-177. April, 1920. 



659. Correns, C. Die geschlechtliche Tendenz der Keimzellen gemischtgeschlechtiger 

 Pflanzen. [Sex tendency of germ-cells in plants of mixed sex.] Zeitschr. Bot. 12: 49-60. 2 

 fig. 1920. 



660. Coulter, J. M. Mutation. [Rev. of: Const antin, J. La mutation. Etat actuel 

 de la question. (Mutation. Present status of the question.) Ann. Sci. Nat. Bot. X. 1: 

 iii-xxix. 1919. (See Bot. Absts. 4, Entry 552.)] Bot. Gaz. 69: 535. June, 1920. 



661. Coulter, M. C. [Rev. of: East, Edward M., and Donald F. Jones. Inbreeding 

 and outbreeding. 14 X 21 cm. 285 p., 46 fig. J. B. Lippincott, Philadelphia, 1919. (See 

 Bot. Absts. 4, Entry 571.)] Bot. Gaz. 69: 530-532. June, 1920. 



662. Cowgill, H. B. Report on tomato and melon breeding. Ann. Rept. Insular Exp. 

 Sta. Porto Rico 1917-18: 96-98. 1919. — Tomato hybrids: Original cross was between vigor- 

 ous local Cherry tomato and Livingston Globe; purpose to secure disease-resistant tomato of 

 good quality suitable to conditions of Porto Rico. Fi plants were intermediate in many prom- 

 inent characters. In F2 318 plants were grown, many closely resembling one or other of par- 

 ents, majority more like Cherry parent. These were in general strong growers and resistant 

 to unfavorable conditions. Partial inverse correlation was noticed between number of fruits 

 in inflorescence and size of fruits; large majority of fruits were shorter in polar diameter than 

 equatorial, which is not true of either parent. Size is at least partially independent of num- 

 ber of cells. No plants had all fruits two-celled like Cherry parent, though some had majority 

 two-celled. Many plants were very promising as to vigor of growth, prolificacy and disease- 

 resistance. — Melon hybrids: Fi of crosses between local oblong melon with soft rind (pistil- 

 late parent) with Hybrid Casaba and Honeydew (staminate). Both of latter have hard rind 

 and are susceptible to downy mildew, though female parent is resistant. Hybrid offspring 

 appeared very resistant, and flavor of fruit was good. Hybrids were more precocious and 

 prolific than local melon. Where Casaba was used as male parent offspring were pyriform and 

 grooved and rough-skinned; when Honeydew was pollen parent hybrid fruits were smooth- 

 skinned, oval and faintly grooved or without grooves. — E. E. Barker. 



663. Cowgill, H. B. Report of the division of agronomy and plant breeding. Ann. Rept. 

 Insular Exp. Sta. Porto Rico 1917-1918: 78-95, 98-104. 1918.— Work with seedling sugar canes 

 was continued to secure several types necessary for different ecological areas of Porto Rico. 

 Several promising new seedling varieties were selected after 3 or 4 years trial. Studies were 

 made of distinguishing botanical characters of cane varieties. 37 crosses were attempted, 15 

 with success, yielding 1794 seedlings. Otaheite and Crystallina were used as seed parents and 

 B-4596, B-347, B-3412, D-117, D-109, and P. R.-207 as pollinators. Viability of nearly all 

 varieties, either crossed or open-pollinated, was relatively low; 45 flats planted with open- 

 pollinated seeds of 6 varieties yielded 5200 seedlings. Describes 6 varieties produced by cross- 

 pollination in 1916. From 1917 seedlings 36 selections were made, 12 from 1914, or 35.5 per 

 cent of that year's seedlings and 4 or 26.6 per cent of 1913 seedlings were selected. These were 

 all planted in to acre plots for comparison with Crystallina. They are now ready to be tested 

 in other parts of Porto Rico. Descriptions of 10 are given. 1912 seedlings were nearly all 

 retained for trial; tables of their yield and analysis are given. Foreign varieties tested for 

 disease resistance on infested soils found all to be susceptible, though some showed varying 

 degrees of resistance. 1500 seedling canes in pots sent to Centrale Coloso and planted in dis- 

 ease infested field, became so badly infected with mottling disease that all were plowed up. — 

 E. E. Barker. 



664. D arrow, Geo. M. Are our raspberries derived from American or European species? 

 Jour. Heredity 11: 179-184. 4 fig. April, 1920. 



