236 HARLEY HARRIS BARTLETT 
Oenothera stenomeres has now been under observation through four 
generations. The starting point of the pure Hne was a half grown 
cauline annual plant which was transplanted to the writer's Bethesda 
garden from Chevy Chase, Maryland, a suburb of Washington, in 
midsummer of 1 9 10. It was not known to be a cruciate plant until 
it flowered, but cruciate plants had been seen in the same general 
locality in 1909, and have been observed frequently every summer since 
then both at Bethesda and Chevy Chase. Ten plants were brought to 
maturity in 191 1, 16 in 1912, and 106 in 1913. Not until the last year 
did the strain show any noteworthy variation, although, to be sure, 
the cultures were very small. In the fourth generation, however, 
there were at least three mutations in the culture of 106 plants. One 
was a practically self-sterile plant, otherwise indistinguishable from 
the type, the second had very large, thick buds and short, thick fruits, 
and the third was a remarkable plant which the writer is inclined to 
consider as perhaps the most striking example of mutation which has 
thus far been reported in any species of Oenothera except Oe. Lamarck- 
iana. This plant was unusually stout and hairy. About midsummer 
the growth of the main stem and of all the branches but one was 
stopped by the development of a large rosette, in every way like the 
winter rosettes of the biennial strains, at the end of each stem. In 
this condition the plant remained through the rest of the summer and 
fall, except that the exceptional branch flowered normally. The form 
proved to be completely fertile to its own pollen and formed large, 
well-filled capsules. The flower buds were densely pubescent, which 
is not the case in the type, but the most remarkable character of the 
plant was that the petals also were densely hairy. All of the cruciate 
Onagrae appear to have a few scattered hairs on the petals (a micro- 
scope is often necessary for their detection) but the petals of this plant 
were so thickly covered with long appressed hairs that they appeared 
canescent in the buds, a day or two before flowering time, when they 
had not yet reached full size. Although larger, the petals of the muta- 
tion were narrow, as in all the other plants of the species, and were 
yellow at maturity. 
A further discussion of this very interesting mutation is reserved 
until its seeds shall have been grown. For the present it will suffice 
Club 41: 79. 1914) has published Oenothera stenopetala, a cruciate-flowered ally 
of Oe. Oakesiana, from the island of Nantucket. It seems to be clearly distinct from 
any of the species treated here. 
