1916] : FORSAITH—ONAGRACEAE 481 
A consideration of pollen conditions in a few of the Onagraceae 
would be far from complete without a brief mention of some species 
of Oenothera. For this reason the distinct Oenothera serrulata Nutt. 
was chosen. This form is considered by some to be sufficiently 
well defined to be regarded as a separate genus, Meriolix. Of 22 
specimens which were examined in the usual way, all were found 
to contain more than 50 per cent of abortive pollen grains. The 
defective grains, as can be seen by reference to fig. 15, are strikingly 
distinct when contrasted with the few fertile microspores. Like- 
wise, the great variability in this genus, as well as an abundance 
of natural hybrids, are so well known and so universally accepted, 
that any further discussion of these phenomena in relation to 
sterility in hybrids would be superfluous. It is significant, never- 
theless, that this species should show so large a percentage of 
defective pollen, and, as such, presents a condition strictly in 
accord with the general principle previously mentioned. 
In contrast to the degenerate pollen development in Oenothera, 
conditions in the anthers of Gongylocarpus fruticulosus Benth. and 
G. rubricaulis Cham. and Schl. should be mentioned. Both of 
these species show uniformly well developed microspores; there 
occur no indications of abortion in any of the grains. Similar 
spore formation was observed in Diplandra lopezoides Hook. and 
Arn., as illustrated in fig. 16. ‘This shows all the cells to be equal 
in size and of uniform development. This naturally leads to the 
conclusion that the plants here mentioned have come from geneti- 
cally pure ancestors. Although the genus Gonyglocarpus is con- 
sidered by ENGLER and PRANTL (11) to be monotypic, 2 species 
were listed at the Gray Herbarium. The presence of two species, 
nevertheless, is unimportant from the standpoint of hybridism. 
G. fruticulosus is found in California, and G. rubricaulis grows near 
Vera Cruz, Mexico. The relative remoteness of these stations 
naturally precludes the impossibility of interfertilization, thus 
insuring in each a pure line of descent. The anatomical evidence 
of uncrossed species likewise supports this conclusion. All 
pollen grains examined showed no indication of degeneration, but 
all were full of protoplasm and of equal magnitude. 
