470 BOTANICAL GAZETTE [DECEMBER 
of Dr Loaca already mentioned, which shows that Mendelian behavior occurred 
n a certain cotton hybrid, BAtts'? has discussed cotton hybrids in a compre- 
Sainte way, showing that at least 21 characteristics of the cotton plants behave 
as unit characters. BALLs declares that, while he does not know the exact num- 
ber of chromosomes in the cotton nucleus, there are certainly not over 20, thus 
placing cotton with Pisum and Antirrhinum, as species in which the number of 
known unit characters exceeds the number of chromosomes. Surtont® has 
carried on extensive crossings in Brassica and found that in a cross between the 
Swede turnip and the Ragged Jack kale there is a strict Mendelian behavior 
in which two unit characters are involved, namely, the fleshy character of the 
root and the curled leaves. The ratio of 9:3:3:1 appeared very clearly in the 
reciprocal hybrids of the cross. The glabrous-leaved brassicas (B. oleracea and 
its allies) would not cross with the hispid-leaved species (B. rapa, B. campestris, 
etc.), and crosses between the turnip and Swede turnip were sterile. 
Nitsson-ERLE’? maintains that practically all of the supposed mutants if 
not all which have been found in wheat, oats, and other similar grains split after 
the Mendelian fashion, and are in reality the results of occasional cross-fertili- 
zations, i.e., of “vicinism.’”’” The most important result reported by NILSSON- 
EHLE is the finding of several instances in wheat and oats, in which apparently 
identical external characters are produced by the presence of two or more inde- 
pendent units, thus resulting in the F, ratios 15:1, 63:1, and perhaps 255:1 
(observed ratio 274:1). In following generations some plants from crosses which 
showed 15:1 in F, give ratios of 3:1, and others again 15:1. Ina red- grained x 
white-grained wheat, which presented the ratio of 63:1 in F,, some plants in F; 
gave again the ratio of 63:1, some 15:1, and some 3: 1, thus confirming the author’s 
conclusion as to the manner in which the ratios 15:1 and 63:1 arise, and showing 
them to be typically Mendelian. The ligula of oats was absent in only one variety 
used in the experiments. This crossed with numerous other varieties sare 
ratios 3:1, 15:1, 63:1, and in one case apparently 255:1 (actually 274: 1), in 
different crosses. He concludes that his results prove the correctness of the 
presence and absence hypothesis, and that not a single fact among his crosses is 
opposed to the ‘‘purity” of the gametes. He also, like Baur, would explain 
the inheritance of certain apparently fluctuating characters as due to Mendelian 
splitting of units having similar functions. 
17 Batis, L., Some aa aspects of cotton breeding. Ann. Rep. Amer. 
Breeders’ Assoc. 5:16-28. 1909 
18 Sutton, ARTHUR W., Brassica crosses. Jour. Linn. Soc. Bot. 38:338-349 
pls. 12. 1909. 
19 Nirsson-Ea ze, H., Einige Ergebnisse von Kreuzungen bei Hafer und Weizen. 
Botaniska Notiser 257~294. 1908. 
Kreuzungsuntersuchungen an Hafer und Weizen. pp. 122. 199% 
Lund: ‘Hakan Ohlssons Buchdruckerei. 
