134 O'NEAL: EMBRYO SAC DEVELOPMENT IN OENOTHERA 
structure and its entrance into the embryo sac. He stated that 
the embryo sac contained from two to four nuclei. He figured 
this condition for Godetia. About three decades after the ap- 
pearance of Hofmeister’s work Kny (18) published in his series 
of charts a description of the earlier phases of the development 
of the ovule in Oenotheria biennis. In 1908, Geerts (15) reported 
the absence of the antipodal cells and one polar nucleus in Oeno- 
thera Lamarckiana; and,in 1909, Modilewski (21) found the 
same condition in Oenothera biennis, Circaea lutetiana, and two 
species of Epilobium. This writer concluded that the tetra- 
nucleate embryo sac was a characteristic of the entire family. 
In 1914, Renner (24), working with Oe. biennis, Oe. Lamarckiana, 
Oe. muricata and various hybrids produced by crossing these 
species, confirmed the findings of Geerts and Modilewski and 
described fertilization and the early development of the embryo. 
The report of the tetra nucleate condition of the embryo sac 
received further confirmation in the same year by the work of 
Werner (29) upon Oe. Lamarckiana, Oe. biennis, Oe, rhizocarpa, Oe. 
tetraptera, and Oe. coccinea, as well as upon certain other members 
of the Onagraceae. The most recent work upon the embryo sac 
of Oenothera is that of Ishikawa* (17), who in 1918 published 
an exhaustive report of his study of this structure, as well as of 
the phenomena of fertilization in Oe. nutans and Oe. Pbycnocar pa 
(the Oe. biennis of the older literature). 
OENOTHERA RUBRINERVIS 
Oenothera rubrinervis was first described by De Vries (27), who 
found the plant appearing in sowings of Oe. Lamarckiana. Its 
presence was first noted by him in 1889. Before 1901 he had 
recorded its appearance 66 times as a mutant from Oe. Lamarcki- | 
ana. Gates (12) mentions the fact that rubrinervis-like plants 
have been found growing wild in Newfoundland, as well as in 
western Colorado (13) and New Mexico. At first, De Vries 
considered _Oe. rubrinervis a “fixed” species, but recently (28) 
he has called it a “half mutant.” He thinks that it has been 
produced “by the copulation of a mutated gamete with a normal 
velutina gamete of O. Lamarckiana.”’ In the same publication 
he showed that Oe. deserens is arising from his strain of Oe. 
* Ishikawa (17) and Gates (12) give extended bibliographies, which may be 
consulted for a general summary of the literature upon the genus Oenothera. 
