244 GENETICS [Bot. Absts., Vol. VI, 



1670. Frtjwirth, C. Handbuch der landwirtschaftlichen Pflanzenziichtung. 3. Die 

 Ziichtung von Kartoffel, Erdbirne, Lein, Hanf, Tabak, Hopfen, Buchweizen, Hiilsenfriichtern 

 und kleeartigen Futterpflanzen. [Handbook of agricultural plant breeding. 3. The breeding 

 of potatoes, Jerusalem artichokes, flax, hemp, tobacco, hops, buckwheat, legumes, and clover- 

 like forage plants.] 3rd ed., 21fi p., 45 fig. Paul Parey: Berlin, 1919. — In present edition of 

 this volume section on potatoes is fundamentally revised. Considerable change is made 

 also in portions devoted to breeding of flax, hops, and tobacco. Presented in this edition for 

 first time is discussion on breeding of Soy beans (Soja). Author touches on his own researches 

 in potatoes, hemp, legumes, and clovers. There is an increase of 17 pages and 10 figures over 

 last edition. [From anonymous review in Zeitschr. Pflanzenzlicht. 7: 222-223. June, 1920.] 

 —J. P. Kelly. 



1671. Frtjwirth, C. Die Saatenanerkennung. [Seed recognition.] Hi + 126 p., 66 fig. 

 Paul Parey: Berlin, 1918.— See Bot. Absts. 6, Entry 1586. 



1672. Gager, C. Stuart. Heredity and evolution in plants. 14 X 20 cm., xi + 265 p., 

 118 fig. P. Blakiston's Son & Co.: Philadelphia, 1920. — Represents essentially a reprinting, 

 with minor modifications, of chapters 31-38 of the author's "Fundamentals of botany," to 

 which have been added a chapter on geographical distribution (p. 139-182) and one on the 

 great groups of plants (pp. 243-251). A classified bibliography of books and a brief list of 

 journals are also new. All but three of the books listed are in English, and the only foreign 

 journals cited are the "New Phytologist," London, and the "Revue general de botanique," 

 Paris.— G. H. Shull. 



1673. Gardner, V. R. Results of bud selection investigations at the Missouri and Oregon 

 experiment stations and their interpretation. Proc. Amer. Soc. Hortic. Sci. 16: 66-70. (1919) 

 1920. — Scions from high- and low-yielding Ben Davis trees (Pyrus malus) proved of equal 

 value. Likewise, ten years selection for high and low yield in a standard strawberry variety 

 had no effect on productiveness. Cases of degeneration in several seedling strawberries are 

 given. This degeneration in one case involved the entire stock; in another case, only a 

 part of the plants of a variety. — Crosses of wild Fragaria chiloensis with a cultivated variety 

 gave mostly seedlings bearing petioles with appressed and ascending pubescence like that of 

 the wild form. Some seedlings had petioles with spreading pubescence like that of the 

 cultivated variety. One seedling bore petioles of both types. Propagations from this seed- 

 ling gave daughter plants, some of which were like the wild form, some like the cultivated 

 variety, and others with petioles of both types. — Author points out importance of eliminating 

 degenerates as a means of keeping a variety up to standard. [See also Bot. Absts. 6, Entry 

 1155.]— Fred Griff ee. 



1674. Gates, R. R. A preliminary account of the meiotic phenomena in the pollen mother- 

 cells and tapetum of lettuce (Lactuca sativa). Proc. Roy. Soc. 91: 216-223. 2 fig. May, 

 1920.- — A study of the pollen development of the Dwarf Perfection lettuce and a rogue from it, 

 revealed no constant cytological difference between the variety and its rogue; but certain 

 interesting features were observed in both. The elongated tapetal cells lie parallel with the 

 longer axes of the loculi. In the binucleate phase of the tapetal cells the nuclei often present 

 in appearance various synaptic stages. Every transition occurs between microspore 

 mother-cells and tapetal cells. The members of a bivalent chromosome lie side by side and 

 chiasmatypy often occurs. The author states that this phenomenon is here described for 

 the first time in plants. There are 9 pairs of chromosomes, which fall into 3 groups as to size. 

 The 10 chromosomes sometimes found in diakinesis may have resulted from the separation 

 of the members of a pair or from a transverse segmentation of one of the bivalent chromo- 

 somes. The number of chromosomes may be reduced to 8 or 7 by a more or less complete 

 fusion, end to end, of two bivalent chromosomes. The manner of coalescence of these chromo- 

 somes furnishes a probable basis for the phenomena of coupling or repulsion. The microspore 

 mother-cells are divided into tetrads by cytoplasmic intrusions from the wall. These have no 

 connection with the spindle. The few pollen grains maturing in a loculus are surrounded 

 by a "cytoplasmic detritus from the tapetum." — Margaret C. Ferguson. 



