No. 547] GENETIC AL STUDIES ON CENOTHEBA 417 



appeared also in all previous F 2 generations that I have 

 grown and presents a most interesting subject for study. 



6. The extreme variants of the cultures would rank as 

 new species different from either parent of the cross and 

 from the F l hybrid plants. Their germinal constitution 

 (provided it is stable) on the hypothesis of unit char- 

 acters apparently must involve the modification of old 

 factors or the creation of whole sets of new factors in 

 large numbers, a degree of complication unfavorable to 

 the hypothesis. 



7. The progeny of the F, hybrid plant 10.30La was 

 very different from that of 10.30L& although these two 

 plants were sisters. What would have been the compli- 

 cations if F 2 generations had been grown from a hundred 

 or a thousand sister plants! 



7. The Peobable Composition of the Cultures of 

 Carter and Company from Evidence Furnished 

 by the Sheet in the Gray Herbarium 



Brief reference was made in a former paper (Davis, 

 '11, p. 228) to a very interesting sheet in the Gray Herba- 

 rium of Harvard University, which shows a plant with 

 characters in part those of (Enothera Lamarckiana, but, 

 in the writer's opinion more largely those of grnnrli flora. 

 This sheet bears notes in the handwriting of Dr. Asa 

 Gray to the following effect— in ink, "(E. Lamarckiana." 

 "Hort. Cantab. 1862," and "from seed of Thompson, 

 Ipswich"; in pencil and probably of a different date 

 "said by English horticulturists to come from Texas." 

 It was the habit of Dr. Gray at that time to use herbarium 

 labels marked Hort. Cantab, and this fact, together with 

 the absence of other writing on the sheet indicates that 

 the plant was grown in the botanical garden at Cam- 

 bridge, Massachusetts. 



The date, 1862, suggested a possible genetic relation- 

 ship of this plant in the Gray Herbarium to the cultures 

 of Messrs. Carter and Company of London about 1860 of 

 plants which were grown for the market under the name 



