rg1t] CURRENT LITERATURE 69 
Davis® believes that O. Lamarckiana does not occur as a native species, 
but that it is a hybrid, probably between forms of O. grandiflora and O. biennis, 
and that it originated in European gardens, or that it may have occurred as a 
wild hybrid. To test this hypothesis he is making numerous crosses between 
different forms of these two species, and selecting those types among the hybrid 
progenies which most closely resemble O. Lamarckiana. He reports that all of 
the hybrid forms thus far produced by him differ from O. Lamarckiana in 
several important points, but that the resemblances of some of them to that 
species are such that the taxonomist would at least place these hybrids next to 
O. Lamarckiana. Davis is not convinced, by the evidence at hand, that the 
plants figured in certain old plates or described in various horticultural maga- 
zines of a century or more ago are to be safely referred to O. Lamarckiana, 
as they have been by several writers. The effort to synthesize O. Lamarckiana 
is being continued by the use of other biotypes of the two chosen species, and 
it is expected that some of these will offer a still closer approach to the desired 
result. Reports on these further studies will be awaited with the greatest 
interest, and especially regarding the capacity of any of the new forms to yield 
a series of true-breeding segregates, such as the forms derived from O. Lamarck- 
zana which are now generally recognized as mutants. 
All students of genetics who have handled the oenotheras in hybridization 
experiments appreciate the fact that they are quite anomalous in their heredi- 
tary behavior, and that they do not clearly follow the simple procedure usually 
observed in the hybrids of other plants and of animals. Under the circum- 
stances, no far-reaching generalizations should be drawn from studies in the 
oenotheras except on the basis of extensive cultures and the most careful 
analysis of results. Gates’? has made some features of O. rubrinervis and o 
a derivative from it, which he calls O. rubricalyx, the basis of generalizations 
regarding the nature of unit-characters, which appear to the reviewer not to 
observe this desired caution. O. rubricalyx differs from O. rubrinervis not 
only in amount of anthocyan in leaves and buds, but also to some extent in its 
distribution, the latter form having a red hypanthium, red midribs of the 
sepals, and red on the ventral surface of rosette-leaves and especially of their 
petioles, in which positions O. rubrinervis has a green or yellowish color. Nine 
cultures from self-fertilized O. rubricalyx gave in each case not only O. rubri- 
calyx, but also O. rubrinervis offspring, though the ratios were not satisfactorily 
determined. The conclusion is reached that therefore O. rubricalyx is inca- 
pable of breeding true. The number of families is too small, however, to war- 
rant this conclusion, for Mendelian expectation would allow six of the nine 
6 Davis, B. M., Genetic studies on Oenothera. II. Some hybrids of Oenothera 
biennis ae o grandiflora that resemble O. Lamarckiana. Amer. Nat. 45:193-233- 
jigs. 18. 
7 pe R. R., Studies on the variability and heritability ee eyo in 
Oenothera. Zeit. f. ad Abstam. Vererb. 4:337-372. pl. 1. figs. 5. 
