216 EXPERIMENT STATION RECOED. 



AGRICULTURAL BOTANY. 



Syllabus of plant families, A. Engler and E. Gilg (SyllaMs der Pflanzen- 

 familien. Berlin, 1912, 7. enl. ed., pp. XXXII+387, figs. 457; noted in Gard. 

 Chron., S. scr., 53 {1913), No. 1370, p. 200).— This contains a list of genera and 

 species of plants arranged according to modern systems of classification. In 

 addition to listing the more important species notes are given on their distribu- 

 tion, properties, uses, etc. 



A list of plants growing without cultivation in Franklin, Hampshire, 

 and Hampden counties, Massachusetts, G. E. Stone {Amherst, Mass., 1913, 

 pp. VII +72). — A list is given of 1,190 native ajid 303 naturalized and adventive 

 species of pteridophytes and spermatophytes known to occur within the three 

 counties which are included in the Connecticut Valley in Massachusetts. 



A possible means of identifying the sex of + and — strains in the mucors, 

 A. F. Blakeslee (Als. in ficience, n. ser., 37 {1913), No. 9-'f9, p. 3S5 ) .—Certain 

 of the hermaphroditic species of the mucors are said to be distinctly heter- 

 tigamic, forming regularly large female gametes and smaller male gametes. 

 By growing the + and — races of an isogamous dioecious species in contrast 

 with such an heterogamic hermaphroditic species, a sexual reaction has been 

 found to occur between female branches of the hermaphrodite and branches of 

 the — race, on the one hand, and between male branches of the hermaphrodite 

 and branches of the + race on the other hand. This reaction would lead one 

 to consider the — race male and the + race female. 



On the inheritance of certain characters in the common groundsel and 

 its segregates, A. H. Trow {Jour. Genetics, 2 {1912), No. 3, pp. 230-276, pis. J,, 

 figs. 4). — A study of the groundsel {Senecio vulgaris) has led the author to 

 consider it an aggregate species which includes many elementary ones. Twelve 

 of these elementary species have been cultivated and maintained pure and true 

 to type for several generations. Six have been studied in detail and are dis- 

 tinguished by descriptive names. Five other forms have proved true to type in 

 cultures, but have been less completely studied. 



It has been found by experiment that the radiate character can be trans- 

 ferred by hybridization and subsequent segregation to nonradiate forms. Hairy 

 varieties, in contrast to radiate ones, are not produced so readily. 



The author in conclusion states that after an investigation extending over six 

 years and including the critical examination of about 10,000 groundsel plants, ha 

 finds it ditficult to estimate, even provisionally, the constitution of a casual 

 wild plant. He believes that a study of the methods of genetics will lay a 

 foundation upon which the evolutionist and taxonomist can build with safety. 



Inheritance of flower size in crosses between species of Nicotiana, E. M. 

 East {Bot. Gaz., 55 {1913), No. 3, pp. 177-188, pis. 5).— A study is reported of 

 crosses made between N. forgetiana and N. alata grandiflora. 



Both these species are said to be almost always naturally self -fertilized and 

 through numerous generations of self-fertilization to have become homozygous 

 in their characters. These self-fertile species, which are perfectly fertile among 

 themselves, gave self-sterile progeny. This fact did not affect the production of 

 an Fa generation, as the Fi plants were perfectly fertile among themselves. 



In N. forgetiana the mean corolla length was 25.6 mm. and N. alata grandi- 

 flora 78.8 mm., while the mean variability of the intermediate Fi generation 

 was 44.3 mm. This variation in the Fi generation was very small, being about 

 the same as that of the parental species. The F^ generation, on the contrary, 

 was very variable, and both grandparental types were reproduced. The length 

 of style and of filament were perfectly correlated with the corolla length, and 



