440 EXPERIIMENT STATION RECORD. [Vol.41 



Gigantism in Nicotiana tabacum and its alternative inheritance, H. A. 

 Allard (Amer. Nat., 53 (1919, No. 626, pp. 218-233).— The occurrence of giant 

 or mammoth tobacco plants, having an abnormally high leaf number and pos- 

 sessing a vegetative period of such length as to preclude normal blossoming 

 in the field, is described. This form is said to have appeared in different 

 commercial varieties, including the Maryland, Cuban, Connecticut Havana, 

 and Sumatra types, as well as in certain varietal and species crosses. Obser- 

 vations on tlie possibilities of combining the mammoth character with other 

 characters of commercial value by crossing mammoth types with common 

 varieties are described in the present paper. The behavior of a number of 

 such crosses and the appearance and behavior of a new mammoth type in a 

 line originating from a species hybrid are discussed in some detail. 



In summarizing the results it is stated that " not only giant or mammoth 

 tj-pes which breed true, but intermediate or hybrid types occur spontaneously 

 which subsequently give rise to a greater or less proportion of mammoth 

 forms." In crosses with normal varieties gigantism behaved as a recessive 

 unit character, appearing in the F2 in the expected 3 : 1 ratio. Fi plants are 

 said to have blossomed invariably and to have exhibited a somewhat higher 

 average number of leaves than the normal parent entering into the cross. 



The Mendelian behavior of aurea cliaracter in a cross between two varieties 

 of Nicotiana rustica, H. A. Allaed {A77ier. Nat., 53 {1919), No. 626, pp. 23Jf- 

 238). — The author records observations on the Fi, F2, and F3 progeny of 

 crosses between a distinctive white-stemmed and a green-stemmed type of 

 N. rustica, begun at Arlington, Va., in 1914, together with the behavior of 

 certain back crosses. The term " aurea " is applied to a peculiar varietal form 

 of chlorosis characteristic of a light, yellowish-green type of A^. rustica, hav- 

 ing white stems and midribs and introduced from Paissia, where it is said to 

 be grown commercially as a pipe and cigarette tobacco. " In this variety of 

 N. rustica, the stems of young plants, especially if they have been somewhat 

 etiolated by crowding, are almost snow white. A cross section of the stems 

 of such plants one month old reveals the fact that this whiteness is not 

 merely superficial, but extends entirely through the stems, whereas in green 

 varieties of N. rustica the internal structure of the stems is green throughout. 

 The cotyledons are decidedly chlorotic, and the leaves have a pale yellowish- 

 green chlorotic appearance which becomes more marked as the plants approacli 

 maturity." The results secured may be summarized as follows: 



In the Fi the aurea type behaved as a simple recessive to the green-stemmed 

 type, the F2 plants segregating into green-stemmed and white-stemmed plants 

 in approximately the expected ratio of 3:1. Some heterozygous individuals 

 were found among the green plants and again segregated into green and 

 aurea types in a 3 : 1 ratio. Extracted aurea recessives of the F2 proved to be 

 homozygous for the white character. Back crosses between a heterozygous Fi 

 and the dominant green type resulted in all green-stemmed plants, while in a 

 similar back cross with the recessive aurea type the progeny consisted of green 

 and aurea plants in about the expected 1 : 1 ratio. 



Tobacco growing" in Ireland, G. N. Keluse (Dept. Agr. and Tech. Instr. Ire- 

 land Jour., 17 {1917), No. 2, pp. 461-466; 18 (1918), No. 3, pp. 296-299; 19 

 {1919), No. 3, pp. 298-302).— The progress of work previously noted (E. S. R., 36, 

 p. r>33) is briefly discussed for the seasons of 1916, 1917, and 1918. 



On the blooming and fertilization of v/heat flowers, C. E. Leighty and T. B. 

 Htjtcheson {Jour. Amcr. Soc. Agron., 11 {1919), No. 4. PP. 143-162, figs. 2). — 

 The authors describe observations made at the Minnesota Experiment Station 

 and the Arlington (Va.) Experiment Farm during the summer of 1014 on the 



