116 GENETICS [Bot. Absts., Vol. IV, 



showed irregular spotting in certain individuals. Criticism is made of Allen's "centers of 

 pigmentation," Morgan's "incomplete dominance," and Bateson's "disappearance of fac- 

 tors in certain areas." Environment may cause factors A (agouti) and C (color) to separate 

 in certain cells thus producing white areas. — P. W. Whiting. 



712. Ragionieri, Attilio. Improvement of Richardia. Gard. Chron. 66: 252-253. Fig. 

 116. Nov. 15, 1919. — Richardia Rehmannii rosea was pollinated by R. Elliottiana. Differ- 

 entiating characteristics were: Small, proliferous, versus large tubers; narrow, lanceolate, 

 short-petioled, versus broad, hastate, long-petioled leaves; few, small, whitish-green, linear 

 markings, versus numerous whitish blotches on the leaves; small, short-stalked, nearly closed, 

 versus large, long-stalked, well open spathes; and light rosy violet, versus yellow spathe-color. 

 The characteristics of R. Elliotliana are given last, and are said to be dominant, except for the 

 yellow color which is "almost recessive." Eighteen of the Fi plants were alike, and had pale 

 cream and rosy violet spathes. The remaining 2 plants were dwarfed and did not flower. 

 In F 2 there were some plants with large well-opened spathes, rosy-violet, purple, orange-yel- 

 low, and yellow shaded violet. The leaves varied greatly in size, and in shape from lanceo- 

 late to hastate. Some F 2 plants had uniform green leaves without light spots or lines. — The 

 above two species crossed readily with R. albomaculala, but could not be crossed with R. 

 africana. — John Belling. 



713. Raunkiaer, C. Uber die verheltnismassige Anzahl mannlicher und weiblicher 

 Individuen bei Rumex thyrsiflorus Fingerh. [On the relative number of male and female 

 individuals in Rumex thyrsiflorus Fingerh.] Kgl. Danske Videnskabernes Selskab. Biol. 

 Meddel. 1 : 3-17. 1918. — In Rumex thyrsiflorus the percentage of female plants is distinctly 

 higher than that of the male plants, the female percentage being between 70 and 95. Dif- 

 ferences as to the female percentage are found in different elementary species of Rumex 

 thyrsiflorus, some of them being rich in females and some others (relatively) poor. Dif- 

 ferences as to the percentage are found from year to year in the same elementary species. 

 The numerical proportion of females to males depends mainly, or entirely, upon the female. 

 The male plants, where differences are found at all, flower earlier than the females. Pollina- 

 tion within the single elementary species seems to weaken the progeny in such way that it 

 flowers later than the progeny from crosses with plants of another elementary species. — 

 0. Winge. 



714. Renner, O. Ueber Sichtbarwerden der Mendelschen Spaltung im Pollen von Oeno- 

 therabastarden. [On the visibility of Mendelian segregation in hybrids of Oenothera.] Ber. 

 Deutsch. Bot. Gesell. 37: 129-135. 1919. — Oenothera Lamarckiana has distinctly larger pollen 

 grains than 0. muricata. In each case the frequency curve has a single and pronounced mode. 

 The starch grains of the pollen in the former species are elongated and spindle-form, in con- 

 trast to the shorter, plumper grains of the latter. The hybrid 0. {Lamarckiana X muricata) 

 gracilis has pollen of two types, one like each parent. The frequency curves for size overlap, 

 but the decisive starch-grain difference shows that the two types of microspores occur in 

 equal numbers. The frequency distribution of sizes has two well marked modes, separated 

 from one another by the same interval as that between the modes for the unhybridized parent 

 forms. It is known thai 1 he pollen of the hybrid is genetically of two types. The possibility 

 of observing segregation in the microscpores is of the highest possible importance in working 

 out the riddles presented by twin hybrids and other hybridization phenomena in Oenothera. 

 —II. II. Bartlett. 



715. Renner, O. [German rev. of: Atkinson-, G. F. Quadruple hybrids in the Fi gen- 

 eration from Oenothera nutans and Oe. pyenocarpa, with the F 2 generations, and back crosses 

 and intercrosses. Genetics 2:213-200. 16 fig. 1917.] Zeitschr. indukt. Abstamm. Vererb. 

 21:180-187. Sept., 1919. 



710. Renneb, O. [German rev. of: Beribert-Nilsson, Nils. Experimented Studien 

 iiber Variabilitat, Spaltung, Artbildung und Evolution in der Gattung Salix. (Experimental 



