No. 3, October, 1921J GENETICS 209 



1322. DuNLOP, W. R. Variation in the banana. Agric. News [Barbados] 20: 87. 1921.— 

 The author notes a few earlier instances of variation in the banana. In 1895 a plant in Trini- 

 dad produced fruit low down on the side of the sucker (pseudostem). A Chinese banana, 

 also in Trinidad, produced a double bunch of fruit, while there is an instance of a plantain 

 from Bombay with 4 tassels of flowers. It is supposed that the 1st named peculiarity has a 

 mechanical explanation while the 2 last-named phenomena are probably instances of the rare 

 dichotomous branching of the IMusas. From Barbados there is reported a bunch of bananas 

 with twisted stem (fruit stalk), probably due to pathological disturbances. However, the 

 most remarkable and interesting peculiarity observed is segregation of colors. The fruit 

 of a variegated sucker observed by the author in Guatemala had the following composition and 

 characteristics: Pure claret-colored (red) fingers, 20; pure green or yellow, 36; half-claret 

 and half-green, 5; and red with green tip, 10. The claret fingers with green tips possessed the 

 pronounced anterior rib with marked constriction at the tip common to the claret, but re- 

 sembled the Gros Michel in size and, to a great extent, in color. The half-claret and half- 

 green fingers resembled the Gros Michel in morphological characters. It is to be noted that 

 the coloring of these fingers was definitely bilaterally asymmetrical. — /. S. Dash. 



1323. Dtjnn, Grace A. A comparative study of the two races of Rhizopus nigricans. 

 Physiol. Res. 2 : 301-339. 1 fig. 1921. — The author has studied chiefly the nutritive require- 

 ments of an individual (+) race and of ^n individual (-) race of Rhizopus nigricans, comparing 

 them in respect to their physiological reactions under the terms "male" and "female." Using 

 dry weight of harvest as the criterion, the best nutrient tested was a solution containing the 

 following ingredients in the molecular concentrations indicated: KH2PO4, 0. 28; NH«N03, 

 0.(M62; MgS04, 0.0497; F2PO4, trace; dextrose, 1.0. The 2 races tested gave about equal 

 dry weight harvests in all the solutions employed where dextrose was the source of carbon. — 

 The 2 races are shown to differ physiologically in 3 respects although "of course the male and 

 female races of other strains of Rhizopus nigricans might not show these differences." (1) 

 They behave complementarily in conjugating; (2) the "male" race produces a greater abun- 

 dance of sporangia in good solutions than does the "female"; (3) the "male" race produces a 

 greater dry weight harvest in solutions where glycerine is the source of carbon. This three- 

 fold generalization is offered as a step toward an analysis of the physiological differences 

 connected with the sexual difference between the 2 races. — A. F. Blakeslee. 



1324. Erikson, Gosta. Gedanken zur Rotkleeziichtung. [Thoughts on red clover breed- 

 ing.] Zeitschr. Pflanzenziicht. 8: 79-85. 1921. — The average red clover crop of Sweden, 

 Norway, and Denmark is but 25-30 per cent of the maximum. This reduction is due in part 

 to improper preparation of hard seed and to improper mixtures of clover with grasses used. 

 The best farmers grow their own seed and sow it without preparation, often in an unhulled 

 condition. — The writer observed that some place strains, in comparative trials, did compara- 

 tively much better in certain years, due mainly to differences of reaction toward soil moisture. 

 — Certain colors, such as gray, characteristic of some strains, are apparently responsible for 

 the easy invasion of certain parasitic organisms. Clover strains with certain colors of seeds, 

 leaves, and stems are recommended. — Locally adapted place strains of red clover develop 

 which often can not be grown successfully even in nearby localities. Red clover seed should 

 not be exchanged or transferred geographically without critical knowledge of controlling 

 factors and reactions to them. — L. R. Waldron. 



1325. FiRBAS, Heinrich. Uber kiinstliche Keiraung des Roggen- und Weizenpollens 

 und seine Haltbarkeit. [Artificial germination of rye and wheat pollen and their longevity.] 

 Zeitschr. Pflanzenziicht. 8: 70-73. 1921. — The author reviews previous findings in regard 

 to the longevity of wheat and rye pollen, and discusses briefly the conditions affecting ger- 

 mination in artificial media and on stigmatic surfaces. It is concluded that temperature, 

 air humidity, and age affect the viability of pollen. — F. P. Bussell. 



1326. FiscHEL, Alfred. Ursachen tierischer Farbkleidung. [Causes of animal coat 

 color.] Arch. Entwicklungsmech. Org. 46: 202-209. 1920. — A criticism is presented of a 



