332 GENETICS [Bot. Absts. 



germinal material so that new variations arise in direction of need, assuming that there may 

 have been previous adaptive modifications of the "parent-body." Defends thesis that 

 special adjustment between organism and environment arose by chance, although chance is 

 not to be defined as "uncaused." Author objects to considering genetics synonymous with 

 Mendelism. [See Bot. Absts. 3, Entry 2518.]— L. B. Walton. 



2203. Svedelius, N. E. Generationsvaxlingens biologiska betydelse. [The biological 

 importance of the alternation of generations.] Botaniska Sektionens af Naturvetenskapliga 

 Studentsallskapets i Uppsala forhandlingar. Svensk Bot. Tidskr. 1918: 487-490. Mar. 19, 

 1919. — Author criticizes theory of Bower and Wettstein on the origin of alternation of gen- 

 erations as connected with the vegetable kingdom's transition and accommodation from life 

 in water to life on land. Among the Phaeophytes the same development concerning the rela- 

 tive condition between gametophyte and sporophyte is to be seen as in the ferns and seed 

 plants. This circumstance however is in these algae not connected with radically changed 

 external conditions of life.— The principal importance of the reduction-division is to make 

 possible new combinations of the chromosomes. (1) When fertilization is compensated by 

 one reduction division only two different combinations of chromosomes are possible. (2) 

 When fertilization is compensated by many reduction-divisions (several mother cells) a great 

 number of combinations are possible. — The origin of a diploid sporophyte by postponement 

 of the reduction division furnishes possibilities for the plant to produce a large number of 

 reduction divisions and by this an increased number of combinations of allelomorphs. Thus 

 the genesis of higher types as a result of this fertilization is made possible. — The theory is 

 supported by the distribution of the two types in the vegetable kingdom. Type 1 includes: 

 Flagellates, Diatomeae centricse, Conjugates and Chlorophyces, haplobiont Rhodophyces 

 and Phycomycetes. Type 2 contains: Diatomeae pennatae, diplobiont Rhodophyces, Thaeo- 

 phyces, Myxomycetes, Ascomycetes and Basidiomycetes (3) and all Bryophytes, Gym.no- 

 sperms and Angiosperms. — Type 1 (one fertilization and one reduction division) thus includes 

 more primitive and simply organized forms of plants. Type 2 (one fertilization and many 

 reduction divisions) contains plants which really have reached a higher degree of evolution. 

 — Possibly the evolution has gone from haploid haplobionts (Spirogyra type) to haploid and 

 diploid diplobionts (Dictyota type) and finally to diploid haplobionts (Fucus, Plumbagella 

 and other phanerogams). — K. V. Ossian Dahlgren. 



2204. Sylvex, N. Nagra anmarkningsvarde enar. [Some peculiar specimens of Juni- 

 perus communis.] Skogsv&rdsforeni. Tidskr. 1918: 656-662. 6 fig. 1918. — Author describes 

 a spontaneous variation of Juniperus communis from Tulseboda in Blekinge (southern Swe- 

 den), that agrees with the cultivated Juniperus communis pendula (B. reflexa Pari.). — K. V. 

 Ossian Dahlgren. 



2205. Transeau, Edgar Xelsox. Science of plant life. 14 X 19 cm., v + 336 p., 194 fig. 

 World Book Co.: New York, 1919. — Pages 220-228 contain six short paragraphs on "plant 

 breeding," "variations," "two kinds of variation," "mutation," "hybridization" (17 lines 

 in which Mendelian inheritance is only vaguely suggested), and "selection." On p. 325 is 

 also a short paragraph on "plant breeding and evolution." — Geo. H. Shull. 



2206. Van Fleet, W. New everbearing strawberries. Jour. Heredity 10: 14-16. 2 fig. 

 Jan., 1919. — Several varieties of strawberries in which the runners are largely suppressed and 

 successive fruiting crowns formed are all descendants of Pan American, a sport or mutation 

 of the Bismark, a variety of Fragaria virginiana type. This everbearing tendency appears 

 in some of the hybrids and seedlings of Pan American. Progressive and Superb are the most 

 popular varieties though they may be deficient in productiveness and plant-making capacity. 

 Seedlings from present everbearing varieties, and crosses with spring-fruiting commercial 

 varieties and varieties of the European Alpine strawberry, Fragaria vesca, which naturally 

 fruits over a long season have been made with the hope of developing varieties of additional 

 value. F. vesca in the European and Mexican Alpine forms has rarely proved worth culti- 

 vating. — Several seedlings of the F. vesca type from seeds forwarded by W. F. Wight from Chile, 



