June, L920] 



GENETICS 333 



showed greater vigor, fruitf nines .and general adaptation than any Alpine hitherto introduced. 

 Plants under the introduction No. 35005 have been disseminated in a limited way for trial. 

 Crosses between it and Chesapeake and Early Jersey Giant were made under glass and 400 

 of the seedlings which fruited in June, 1«.U7, showed high average as June-fruiting varieties, 

 but with no obvious tendency toward continuous fruiting. Runners from two of the best 

 were brought into bloom and again pollinated with 33005 and of 150 seedlings, 4 bore handsome 

 large berries continuously from July until November and a good supply of vigorous runners. 

 If then, the everbearing Pan American is a mutant, it is evident that everbearing forms may 

 be obtained from other sources. [See Bot. Absts. 2, Entry 732; 3, Entry 74.]— M. ./. Dor 



2207. Van Fleet, Walter. Progress in breeding Freesias. Jour. Intermit. Card. Club 

 3 : 232-239. June, 1919.— Author notes that "the original wild F. refracla was introduced into 

 cultivation about 1816. It has a rather tortuous horizontal scape, with 5 or more blooms, 

 bulging corolla tubes pointing irregularly up or down, and is lurid greenish-yellow with 

 pronounced orange blotch, rather than clear white in its coloring." Florists soon started 

 improvement. Forty years ago a superior variety appeared which had larger foliage and well 

 shaped, almost pure white flowers, though retaining the deep yellow blotch. It came to be 

 known as F. refracla alba, and it has since become the common garden variety. Further se- 

 lection developed the pure white variety "Purity." — The yellow of the F. refracta was unpop- 

 ular. A vigorous garden variety was found in a neglected Italian garden, which produced 

 large well shaped blooms, with wide tubes, sulphur to deep yellow in color, free from greenish 

 shades. It was named F. Leichtlinii. From it has been bred a charming yellow variety F. 

 Chapmanii. By crossing F. Leichtlinii with F. Armstrongii, a new pink-flowering species, 

 there has lately arisen some remarkable apricot-colored or flaming orange varieties. — Pink 

 forms have been offered by nurserymen, but they are not well established and prove to be 

 variants of F. refracta alba. — Author's work has been with F. Armstrongii, hybridizing it 

 with other species. He has secured a large range of colors, including brilliant yellow, bright 

 orange, copper red, various pink shades, rosy purple, and violet blue. Variations have also 

 been obtained in form and color plan so that some resemble "star phlox" while others show 

 indications of doubling. A desirable variation is a two-ranked cluster, which somewhat 

 resembles an enlarged Trailing Arbutus. The best of the new varieties are usually sterile but 

 may be propagated by corms. [See also anonymous rev.: Gard. Chron. 66: 95. 1919. (See 

 also Bot. Absts. 3, Entry 2077.)]— C. E. Myers. 



2208. von Hofsten, N. Arftlighetslara. [Genetics.] 17 X 26 cm., viii + 506 p., 191 fig. 

 1 colored pi. P. A. Norstedt & Soners forlag: Stockholm, 1919. — This text-book is divided 

 into five sections. In the first section — "phenotype and genotype," — author treats the the- 

 ory of transformation and of continuation, norm of reaction and modifications, the difference 

 between personal qualities (phenotype) and genotypical constitution, pure lines and popu- 

 lations, and other related questions. — The second section (14 chapters) treats of hybridization. 

 After an explanation of the principles of Mendelism the author points out very particularly 

 the relation between genetic qualities and exterior properties, polymeric factors, presence- 

 absence-hypothesis and the nature of the factors, attempting to differentiate between factors 

 — the formal units, — and genes, the real units, the nature of which is unknown. After treat- 

 ing of linkage phenomena, species hybrids, etc., this section ends with a chapter "On the tra- 

 ditional views of inheritance in the light of modern genetics," in which the author explains 

 and criticizes such expressions as variation, correlation, latency and atavism. — The third 

 section deals with cytology, giving schematic tables (originals) and treats of the reduction 

 division and different opinions about its nature; discusses segregation of hybrids as a cyto- 

 logical procedure (Morgan's crossing-over hypothesis) ; considers the experiments of Federly 

 and others on the origin of constant hybrids, etc. Then follow three chapters on inheritance 

 of sex and the chromosomes which determine sex. The author is not satisfied with the rather 

 complicated sex formulae of Goldschmidt and criticizes his potency hypothesis. Author 

 uses the formulae 9 FF, cfF/resp. <?MM, 9 Mm, which formulae correspond with cytological 

 facts; he holds however that the sex-chromosomes do not determine sex itself and that un- 



