October 11, 1912] 



SCIENCE 



483 



site, the stamens are caused to develop and the 

 ovary is reduced, while the form of the flower of a 

 male which is infected is not altered. In order to 

 test this suggestion, I planted some ustilaginized 

 plants in my garden in the late summer of 1910, 

 and put with them some uninfected plants which 

 I attempted to infect by sprinkling them with 

 spores and liy rubbing spores into parts of the 

 stem from which I had scraped away the epi- 

 dermis. The results were as follows: Of seven 

 females which I attempted to inoculate in August, 

 1910, one became infected, and had the typical 

 "hermaphrodite" form of flower in October, but 

 in June, 1911, was again quite free from Ustilago, 

 and had typical female flowers. A second female 

 plant showed infection in June, 1911, but only on 

 part of the plant; one branch was quite clean and 

 had typical female flowers, the rest of the plant 

 was infected and had ' ' hermaphrodite ' ' flowers. 



Of eight male plants which were inoculated in 

 August, three showed some infected flowers before 

 the end of September; the anthers contained 

 Vstilago spores, but there was no change from 

 the male type of flower. Three of these eight 

 plants were dead in June, 1911 ; one of the re- 

 maining five was infected. 



Of five ustilaginized plants transferred to the 

 garden, four had the hermaphrodite type of flower 

 and one the male. One of the hermaphrodites so 

 iar recovered in September, 1910, as to set some 

 seed; in 1911 all were still infected. One of 

 them had some branches with hermaphrodite 

 flowers containing large ovary, short styles and 

 stamens with little or no pollen, but without 

 Vstilago spores, while the rest of the plant had 

 flowers with anthers full of spores, and the ovary 

 and styles more reduced. 



These observations seem to prove that infection 

 with Vstilago can turn the female flower into the 

 apparent hermaphrodite, but that no production 

 of female organs takes place in a male flower 

 when it becomes infected. 



l. doncastek 



Cambridge, England 



The occurrence of uninfected hermaphrodite 

 ■flowers on one of Doncaster's original infected 

 plants may possibly indicate that this plant 

 was not a female previous to its infection, but 

 a hermaphrodite. If it were possible to secure 

 pollen from a ustilaginized female, certain 

 genetic problems of very great interest might- 

 be solved. It is of great theoretic importance 



to know whether infection by Ustilago affects 

 the genotypic nature of the host. If the effect 

 is purely somatic, as seems to me the more 

 probable, the offspring of a self -fertilized her- 

 maphroditic female, or of a normal female fer- 

 tilized by sperms from a hermaphroditic 

 female, should consist only of females (if un- 

 infected), and not of females and hermaphro- 

 dites, as I have shown to be the case when a 

 female is fertilized by a hermaphroditic male. 

 If infection by Ustilago produces a genotypic 

 modification, it would be interesting to know 

 whether such induced hermaphrodites are 

 homozygous like the females by whose modifi- 

 cation they are produced; they should in that 

 case yield only hermaphrodite offspring. Her- 

 maphroditic males produce both female and 

 hermaphroditic male offspring, because the 

 males are sex-heterozygotes. 



As I have been fortunate enough thus far 

 not to have a single infection from Ustilago 

 among the many thousands of individuals of 

 Lychnis dioica which have been involved in 

 my cultures during the past seven years, I do 

 not care to take up at present the here sug- 

 gested line of investigation upon ustilaginized 

 females. I do not wish to jeopardize by im- 

 porting infected material, the solution of many 

 other genetic problems now under investiga- 

 tion, but I hope that Professor Doncaster or 

 some one else who is in a position to do so, 

 will give attention to breeding from hermaph- 

 roditic females if this proves to be technically 

 possible. Geo. H. Shull 



SCIENTIFIC JOVMNALS AND ABTICLES 

 Contents of the September number of Ter- 

 restrial Magnetism and Atmospheric Electric- 

 ity are as follows : " A New Type of Compass 

 Declinometer," E. L. Faris; "The Physical 

 Theory of the Earth's Magnetic and Electric 

 Phenomena, No. VI.: On the Origin of the 

 Earth's Magnetic Field," L. A. Bauer; "Mag- 

 netic Declinations and Chart Corrections Ob- 

 tained by the Carnegie from Batavia to Ma- 

 nila, and Thence to Suva, Fiji, November, 

 1911, to June 5, 1912," L. A. Bauer and W. J. 

 Peters ; " Eesultate der Inklinationsbeobacht- 



