218 GENETICS [Bot. Absts., Vol. V, 



almost exactly a 1 : 15 ratio. This suggested at once the presence of two independently 

 inherited factors for the normal texture, the coriacea type being produced only when these 

 two factors K and L were absent. Subsequent breeding has shown that coriacea breeds true 

 when selfed, and has also confirmed the interpretation of this as a third case of duplication of 

 factors in this species. The two characters previously shown to be thus constituted are the 

 triangular form of capsule, and the division of the leaf to the midrib which brings to light 

 the characteristic lobing found in the form designated rhomboidea. The duplication of the 

 capsule determiners is practically universal while that of the leaf-lobe factor is less frequently 

 found. Studies on the coriacea character are still too limited in extent to justify a statement 

 as to the prevalence of duplication of the factor for the usual texture of the leaves. — George 

 H. Shull. 



1649. Siemens, H. W. Rashygienens biologiska grundvalar. [Biological foundations of 

 race hygiene.] 98 p. Gleerup: Lund, 1918. 



1650. Siemens. [German rev. of: Haecker, V. Die Erblichkeit im Mannesstamm und 

 der vaterrechtliche Familienbegriff. (Inheritance in man and the male-line concept of the 

 family.) 32 p. Gustav Fischer: Jena, 1917.] Zeitschr. indukt. Abstamm. Vererb. 22: 213. 

 Mar., 1920. 



1651. Sirks, M. J. Verwantschap als biologisch vraagstuk. [Relationship as a biological 

 problem.] Genetica 2: 27-50. Jan., 1920. 



1652. Sirks, M. J. De analyse van een spontane boonenhybride. [Analysis of a spontane- 

 ous bean hybrid.] Genetica 2: 97-114. Mar., 1920. 



1653. Sirks, M. J. Uit het Instituut voor Veredeling van Landbouwgewassen. Vergelijk- 

 ing van gerst en tarwerassen, van het Instituut afkomstig met andere voortrefflelijke rassen 

 van deze gewassen 1915-1917. [From the Institute for the Improvement of Agricultural Plants. 

 Comparison of barley and wheat varieties originating from the Institute with other superior 

 races of these plants 1915-1917.] Med. Landb.-Hoogeschool Wageningen 14: 1-34, 210-232. 

 1918. 



1654. Sirks, M. J., and J. Bijhotjwer. Onderzoekingen over de eenheid der linne- 

 aansche soort Chrysanthemum leucanthemum L. [Investigation of the homogeneity of the Lin- 

 nean species Chrysanthemum leucanthemum L.] Genetica 1: 401-442. Sept., 1919. 



1655. Soler, Rafael Angel. Cultivo del tomate. [Tomato culture.] Revist. Agric. 

 Com. y Trab. 2: 479-483. 8 fig. 1919. 



1656. Sperlich, Adolf. Die Fahigkeit der Linienerhaltung (phyletische Potenz), ein auf 

 die Nachkommenschaft von Saisonpfianzen mit festem Rhythmus ungleichmassig iibergehender 

 Faktor. [Capacity to maintain lines (phyletic potency), a factor distributed irregularly to the 

 offspring of plants with fixed seasonal rhythm.] Sitzungsber. Akad. Wiss. Wien 128: 379. 1919. 

 —See Bot. Absts. 5, Entry 1559. 



1657. Sperlich, Adolf. Uber den Einfluss des Quellungszeitpunktes, von Treibmitteln 

 und des Lichtes auf die Samenkeimung von Alectorolophus hirsutus All.: Charakterisierung 

 der Samenruhe. [On the influence of the time of application of forcing -agents and of light on the 

 germination of seeds of Alectorolophus hirsutus. Characterization of seed rest.] Sitzungsber. 

 Akad. Wiss. Wien 128: 477. 1919.— See Bot. Absts. 5, Entry 1559. 



1658. Spragg, Frank A. The spread of Rosen rye. Jour. Heredity 11: 42-44. 1 fig. 

 Jan., 1920. 



1659. Stein, E. [German rev. of: Klebahn, H. Impfversuche mit Pfropfbastarden. 

 (Infection experiments with graft hybrids.) Flora 11-12: 418-430. 1918.] Zeitschr. indukt. 

 Abstamm. Vererb. 22 : 304. May, 1920.— See also Bot. Absts. 3, Entry 2124. 



