* 
1916] CURRENT LITERATURE . 331 
ae medley of species, for on mycologists long since an undecipherable 
rebus.—GEo. F. ATKINSON 
Patrogenesis.—CoLiins and KEMprTon,” working on intergeneric hybrid- 
ism in the tribe Maydeae, have had the great good fortune to bring to light a 
new case of the phenomenon discovered in Fragaria by MILLARDET, and 
termed by him “‘hybridation sans croisement ou fausse hybridation.”” The 
hybrid Tripsacum dactyloides X Euchlaena mexicana, carried through 3 genera- 
Characters of Euchlaena appeared with the a leaves, and in further stages 
of development the plant was an almost no hlaena. 
In attempting to explain the ae exclusion of maternal characters 
from the hybrid, the authors have discussed two hypotheses: (1) that the 
Euchlaena characters have completely masked those of the Tripsacum, and (2) 
that the embryo of the original hybrid . only from the male nucleus, 
which must be regarded as having dispossessed the female nucleus with 
which it would have been expected to faite: Cottins and Kempton 
adopt the latter hypothesis, and look upon their hybrid as exemplifying a new 
type of inheritance, which they call ‘‘patrogenesis” in order to place the phe- 
nomenon in what they regard as a proper contrast with parthenogenesis. 
We may well doubt, in the absence of cytological data, whether this explana- 
- tion is probable enough to warrant the introduction of a new term. BaTEson’s 
terms monolepsis and amphilepsis, indicating hybrids in which the characters 
are brought in respectively from only one or from both parents, have already 
been introduced, and have the advantage that they imply nothing as to cyto- 
logical conditions. 
Maternal monolepsis is well known in the Orchidaceae, especially in the 
intergeneric hybrids between Zygopetalum Mackayi and species of Odonto- 
glossum, Lycaste, and Oncidium. Paternal monolepsis is a rarer phenomenon, 
and its discovery in intergeneric grass hybrids is most interesting. That it is 
to be explained by merogony, however, should not be too incautiously assumed. 
It will be recalled that a similar explanation of DeVries’ patroclinic hybrids 
in Ocenothera was brought forward, with even some show of cytological evidence, 
but was afterward disproved. 
In the first hybrid generation Cottins and Kempron tus only one plant 
of their TripsacumXEuchlaena. There is no evidence, therefore, that this 
generation may not consist normally of more than one type, as in the case of 
many Oenothera hybrids. Certain evidence obtained by CoLtins and KEMPTON 
themselves almost tempts one to predict that twin hybrids will be found if it 
is possible to get large enough progenies. 
** CoLtins, G. N., and Kempton, J. H., Patrogenesis. Jour. Heredity 7: 106-118. 
I9g16. 
