1915] BARTLETT—MASS MUTATION 443 
DeVries is in essentials the same.? Another case is provided by 
O. stenomeres mut. lasiopetala.2 HERIBERT-Nitsson® has recently 
described several new mutations from O. Lamarckiana (‘‘hetero- 
game Kombinanten” dependens, undulata, stricta, etc.) which 
probably show the typical /afa type of inheritance, although he 
erroneously concludes that the repeated segregation of O. Lamarck- 
zana from these mutations in each generation is due to the exist- 
ence of two types of functioning gametes on the male rather than 
on the female side. 
It must not be inferred from the similarity of the names that 
mut. /atifolia is a parallel variation to O. lata DeVries. Such is 
not the case. Its characters are quite different. Both mut. 
latifolia and mut. angustifolia will be described and illustrated in a 
future article. 
As in the case of mut. angustifolia, the progeny of mut. latifolia 
from the mass mutating strain contained the expected types, f. 
typica and mut. latifolia, together with the characteristic mutations. 
The latter did not show differences among themselves which would 
enable one to classify them as modified typica or modified Jatifolia, 
as the case might be. The mother plant belonged to the F, genera- 
tion from Lexington E, and showed about the same degree of muta- 
bility as the ¢ypica sister plant, Lexington E-5 (see table II). The 
data for mut. latifolia are summarized in table V. 
Mut. gigas ——E. G. ArZBERGER’S discovery that this mutation 
has 28 chromosomes has already been announced.” The count 
has been made only in one plant, Lexington E-5-238 (figs. 5 and 14), 
belonging to the mass mutant strain. An apparently identical 
mutation in one of the other strains has appeared this summer 
(1915), but its heredity is unknown. Mut. gigas is treated, there- 
fore, as a non-characteristic mutation. Only 196 seeds were 
7For the latest treatment of these mutations see DeVries, Gruppenweise 
Artbildung. pp. 244-26 
8 Bartrett, H. H., The mutations of Oenothera stenomeres. Amer. Jour. Bot. 2: 
— TQI5. 
HERIBERT-NItSSON, N., DieS I der Oenothera Lamarckiana 
bunds Universitets Arsskrift. NF. Ava. 3 2.30! Bost, . pp. 132. IQIs. 
* Barttetr, H. H., The experimental study of genetic relationships. Amer. 
Jour, Bot. 2:132-155. 1915 (see p. 143). 
