1915] BARTLETT—MUTATION IN OENOTHERA 121 
grains had accidentally reached the stigmas of the mother plants. 
This hypothesis was tested by crossing O. pratincola with O. numis- 
matica. As already stated, these two species were the only Onagras 
which the writer found at Lexington. The latter, furthermore, is 
Fic. 17.—F, eS of — G, pan 27, Oenothera pratincola; four mutations 
are shown, G-50 G-53, mut. rubricentra; Gas. mut. mitida; G-52, mut. num- 
mularia; the es srs are a pical O. pratincola. 
suspiciously similar in several characters to mut. nwmmularia, as 
may be seen by comparing the characters already recorded. The 
cross O. pratincola 2 X O. numismatica 2 was conspicuously fertile; 
326 seeds from one capsule gave a culture of 222 plants, consisting 
