1916] AGRICULTUEAL BOTANY. 329 



is said to differ from others in tliat it is based on actual physiological experi- 

 mentation, it talies account of the general principle of temperature minima, op- 

 tima, and maxima, and it shows a much gi-eater rate of increase for the index 

 value with rising temperature between 35.6 and 89.6° F. (2 to 32° C.) than does 

 either of the other systems to which, on whole, it is considered preferable. 



By the use of these new indices, physiological summation indices of tempera- 

 ture efficiency for plant growth have been obtained for many stations in the 

 United States, and these have been charted to give a new temperature zone 

 map of the country. It is thought that the physiological system of indices gives 

 tlie nearest approach yet made to a true expression of the relation of tempera- 

 ture to plant growth. 



Acacia seedlings, R. H. Cambage (Jour, and Proc. Roy. Soc. N. S. Wales, 49 

 {1915), pt. 1, pp. 81-121, pis. 5, figs. 5). — The author gives details obtained by 

 him in the study of species of Acacia as met with in Australia, where mem- 

 bers of this genus show various forms and degrees of variation of the sev- 

 eral parts, presumably under the influence of the peculiar conditions there 

 prevailing. 



Multiple leaves in clover, J. Pekribaz (Bui. Soc. Vaud. Set. Nat., 5. ser., 

 50 (1914). ^0. 182, pp. 15-22, fig. 1). — The author concludes a discussion of his 

 observations by stating that the appearance of supplementary leaflets in the 

 different species of clover is due to heredity or to nutritive factors. These 

 may be distinguished, as the latter appear on the same plan as the normal 

 growth while the former appear on a different plan. 



Variations in flowers of Iris, R. Pirotta (Atti R. Accad. Lincei, Rend. Cl. 

 Sci. Fis., Mat. e Nat., 5. ser., 24 (1915), I, No. 9, pp. 897, S98).— Discussing 

 the appearance in Iris flowers of flecks, spots, or lines, which in some cases 

 were even showy, varying in form, size, number, and position, or sometimes 

 lacking in successive seasons, the author mentions his more recent observations 

 of other variations, which are as yet incomplete. 



On the inheritance of the flowering' time in peas and rice, Y. Hoshino 

 (Jour. Col. Agr. Tohoku Imp. Univ., 6 (1915), No. 9, pp. 229-288, pis. 5).— Since 

 1907 the author has carried on genetical studies with rice and peas, his work 

 bearing upon the theory of a multiple factor. 



It is claimed that his experimentation has demonstrated the fixity of the 

 character of flowering time in the original varieties of peas and the presence 

 of two pure lines in the population of one variety. Flowering time in the Fi 

 generation inclines toward the late parent in peas, toward the early one in 

 rice. The variation range of F2 families covers the combined range of both 

 parent varieties, but their variation type is not the ordinary one. The inher- 

 itance of flowering time follows the Mendelian law in the Fs and F* generations. 

 As an explanation of the inheritance of flowering time in peas, the author sug- 

 gests the presence of two Mendelian factors which differ in their effects, and 

 gametic contamination caused by hybridization whose nature is not yet ex- 

 plainable. From a study of the variation types in peas, it is thought that the 

 hereditary difference of the two pure lines is qualitative and not quantitative. A 

 correlation is noted between flowering time and flower color in peas, which is 

 thought to be explainable by assuming gametic coupling between the color 

 factor and one of the two factors for flowering time. 



A bud variation of the scarlet runner, J. Reinke (Ber. Deitt. Bot. Gesell., 

 33 (1915), No. 7, pp. 324-348). — An account with discussion is given of the 

 appearance in 1913 of a strain of Phaseolus mnltiflorus, some of the upper 

 inflorescences of which bore white corollas, also further observations upon 

 phases of development and heredity in the progeny. 



