312 GENETICS [Bot. AbstSv 



factors is suggested. Oe.franciscana and Oe. Lamarckiana mut. velutina behave as Oe. Hook- 

 eri in crosses with Oe. biennis. Oe. suaveolens behaves as Oe. biennis in crosses with Oe. Hookeri 

 with following exceptions — appearance in rubiennis Fi of a narrow-leaved (constant) mutant 

 and in F 2 of mutants (1) lutescens, (2) small-leaved, and (3) aurea, showy race with golden foli- 

 age.— Oe. Cockerelli in all crosses fails to produce the splitting hybrids characteristic of Oe. 

 Hookeri crosses. — Oe. Hookeri T. & G., Oe.franciscana (Bartlett) and Oe. Lamarckiana mut. 

 velutina {Oe. mut. blandina), three large-flowering species, produce splitting laeta and split- 

 ting rubiennis. These split into (1) splitting type and (2) type of other grandparent. Laeta 

 and rubiennis are constant in no observed case. Apart from rare Mendelian segregation,, 

 other Oenothera hybrids are constant. — Paul A. Warren. 



2112. de Vries, Hugo. Oenothera Lamarckiana mut. simplex. Ber. Deutsch. Bot. Ges.. 

 37: 65-73. May 15, 1919.— In 1906 author observed a new mutant form in a pure bred family 

 of Oenothera Lamarckiana mut. oblonga which in many respects paralleled his Oe. Lamarck- 

 iana mut. velutina (syn : Oe. blandina) . Like the latter, it yielded very few sterile seeds (about 

 S7 per cent with living germs) and produced twin forms when crossed. The new type, which 

 he calls Oe. Lamarckiana mut. simplex, is regarded as an important one, since, unlike Oe. 

 velutina, it has retained the mutability of Oe. Lamarckiana. In a culture of 2000 seedlings of 

 the fourth generation derived from pure-bred seed, he recognized the following mutants: 

 semigigas nanella, lata, scinlillans, linearis, deserens, metallica and secunda; essentially the 

 same mutants as produced by the mother species. Though Oe. rubrinervis and Oe. oblonga 

 were absent, Oe. deserens, another brittle form, appeared in the place of the former, and Oe. 

 metallica in the place of the latter. Author discusses the gametic origin of Oe. Lamarckiana, 

 Oe. mut. simplex and several derivatives of each, concluding that the former arose through 

 mutation and is not hybrid resulting from a cross between two earlier races; also that Oe. 

 mut. simplex is a homozygous, mutating race. — Anne M. Lutz 



2113. de Vries, Hugo. [Rev. of: Ernst, Alfred. Bastardierung als Ursache der 

 Apogamie im Pflanzenreich. (Hybridization as the cause of apogamy in the plant kingdom.) 

 Svo, xv +650 p., 2 pi. ,172 fig. Gustav Fischer: Jena, 1918.] Science 49: 381-382. April, 1919. 

 — Some investigators assume that one of the chief causes of mutation is to be looked for in 

 crossing, while others think that crosses are too rare in nature to have had any appreciable 

 effect in the production of new species, except for the polymorphous genera. The best way to 

 decide the question is to study the influence of hybridizing on the origin of a new character, 

 viz., apogamy, by means of artificial crosses. The book gives a full description of all known 

 cases of apogamy, including algae, fungi, Marsilia, Antennaria, Alchemilla and Hieracium. 

 The doubling of chromosomes, the terminology of parthenogenesis, nucellar embryos, les- 

 sened fertility and many other effects of hybridizing and vegetative propagation are exten- 

 sively dealt with. The author concludes that Chara crinita seems to afford the best material 

 for further studies, and he gives a review of the mode of propagation of this alga. [See also 

 Bot. Absts. 3, Entry 2151.]— A.//. Chivers. 



2114. de Vries, II. Halbmutanten und Massenmutationen. [Half-mutants and mass 

 mutations.] Ber. Deutsch. Bot. Ges. 36: 193-199. 1918.— No species or varieties have been 

 proved to have been produced by fluctuating variations. Certain mutations are established 

 (investigations of Baur, Cockerell, Babcock and Morgan cited). Mass mutation and 

 half-mutants are assumed to be the starting point of these mutations. Mass mutation is 

 the production of new types, not in 1 per cent or less, but in higher percentages of the progeny. 

 Author assumes certain gametes to be mutated before fertilization (premutation). Thus an 

 individual mutant is produced by the fusion of two mutated gametes, a half-mutant by the 

 fusion of a mutated with a normal gamete. Half-mutants split in true Mendelian fashion. 

 Oenothera gigas selfed gives constant dwarf types in 1-2 per cent of offspring. Remainder of 

 progeny is (1) pure gigas type and (2) half-mutants which, when selfed, split into (1) pure 

 gigas, (2) half-mutants and (3) pure dwarfs in a 1 : 2 : 1 ratio. Half-mutants are thus hy- 

 brid-mutants but from gametes of the same origin. Baden corn, which for six generations 



