Maech 27, 1908] 



SCIENCE 



509 



later stages of estraseminal life of corn 

 plant. 



(h) Bunt of Wheat. — Seedling infection. 

 Infection is specialized to stem top meristem. 

 It occurs only in earliest stages of extrasem- 

 inal life of host plant. 



(c) Loose Smuts of Wheat and Barley. — 

 Floral or intraseminal infection. Infection 

 also specialized to the stem, the growing point 

 of the meristem. It occurs in an early stage 

 of intraseminal life of host plant. 



(a) Fungus of Lolium temulentum. — Meth- 

 od and occurrence of infection as in type (c), 

 hut spore formation probahly abandoned and 

 the beginnings of a symbiosis possibly estab- 

 lished. 



Many problems relating to the details of 

 type (c) are yet unsolved, as for instance, the 

 behavior of spores in regard to stigmas, and 

 the results of different periods of infection. 



The second paper on the program was by 

 Professor Bruce Fink : " Present Problems in 

 American Lichenology." Professor Fink 

 called attention to the lack of workers in the 

 field of American lichenology, caused in all 

 probability by the fact that the subject has 

 little economic significance. The literature 

 on this branch is unarranged and even uncol- 

 lected, and the speaker is now engaged in 

 studying the literature bearing on the subject. 

 Up to the present time he has collected about 

 500 titles. The structure of the lichens inter- 

 feres with the ordinary technique of sectioning 

 and staining, but these difficulties are not 

 more serious than those met with in the study 

 of fungi, which have been for the most part 

 overcome. There is great confusion in the 

 nomenclature and classification of lichens; 

 and no agreement has been reached as to the 

 limits of genera and the way in which types 

 can be fixed. Lichens are the first vegetation 

 appearing on unoccupied land, and are of fun- 

 damental importance ecologically. Their re- 

 lation to soil and subsequent vegetation has, 

 however, been little studied. The old problem 

 of the relation of the symbionts in the lichens, 

 whether mutually beneficial or antagonistic, is 

 still unsolved. With the exception of the area 

 about New Bedford, Massachusetts, very few 

 localities have been carefully studied in rela- 



tion to their lichen flora. Professor Fink has 

 himself listed some 500 species from Minne- 

 sota. He concluded his paper with a plea for 

 greater popularization of the study of lichen- 

 ology. 



This ended the evening's program. At the 

 luncheon which was served Dr. Freeman ad- 

 dressed the society informally, taking leave of 

 his associates on the eve of his departure for 

 his new post at the University of Minnesota. 

 W. E. Safford, 

 Corresponding Secretary 



DISCUSSION AND CORRESPONDENCE 



INHERITANCE OF FLUCTUATING VARIATIONS 



To THE Editor of Science : In the issue of 

 Science for January 31 Professor Bigelow 

 asks Dr. Ortmann how he would account for 

 correlation between parents and offspring in 

 cases of fluctuating variations, if variations 

 of this type are not transmitted. I do not 

 wish to answer this question for Dr. Ortmann, 

 but I do wish to call attention to some con- 

 fusion in the use of the term " fluctuating 

 variation." It is necessary for us to agree on 

 its meaning in order to avoid misunderstand- 

 ings. Let us consider for a moment the dif- 

 ferent types of variation and decide on which 

 of them may properly be included under the 

 term " fluctuating variations." In the first 

 place, there are some variations which I think 

 we will all agree are not included. Two of 

 these relate to real evolutionary changes. 

 First, organisms in their phylogenetie devel- 

 opment acquire new characters. We may 

 mention the horns of cattle as an example. 

 The development of hair or feathers as an 

 external covering is another example. Even 

 these characters may be looked upon as, in a 

 sense, modifications of previously existing 

 ones. Second, a character already present 

 may undergo permanent change. In this way 

 we get the various shapes of leaves, say of the 

 genus Quercus. We may also include here the 

 loss of certain characters which were formerly 

 possessed. For instance, red swine have lost 

 the power of producing black pigment. It is 

 conceivable that very little of the variation 

 we find in a generation of individuals from 



