28 
relationships of the various forms by hybridological and other 
rental 
the 
mutants described by deVries, some of which have had an inde- 
pendent existence for 18 years. In addition pedigree-cultures 
have been carried on for the purpose of detecting the occurrencés 
of mutants in other speces. 
An investigation of the above scope entails a great amount of 
detail and during the past season J have been so fortunate as to 
have secured the codperation of Dr. G. H. Schull, Miss A. M. 
Vail and Dr. J. K. Small. 
An outline of the ae recently obtained was presented to 
the Botanical Society of America at Phila cari 2 31, 
1904, and an extensive paper giving full details, erous 
illustrations, is now in press and will be ee . the 
Carnegie Institution.* 
continuance of the effort to trace the nativity of Lamarck’s 
evening-primrose has resulted in the discovery of records and 
once that make it appear foly, conclasive that it is a 
ing from near the Atlantic coast wom rd through the Gulf 
States to central Texas, and that it has remained unchanged 
since its first introduction into eau more than a century 
ago. Three or four generations of pure pedigree-cultures are 
usually supposed to be sufficient to test the purity of any strain 
of plants, with especial regard to hybridizations. Lamarck’s 
evening-primrose has been carefully guarded against possible 
hybridizations since 1884, and perhaps no plant is known in 
which the purity of the parental strain has been so critically 
examined. 
Having come upon a description by Bartram of his discovery 
of an evening-primrose, which he characterized as ‘the | 
pompous and brilliant herbaceous plant yet known to exist” 
“* MacDo ugal, D. T., assisted by Miss A. M. Vail, Dr. G. H. Shull and Dr. J. K. 
oar, Mutants and Hybrids of the CEnotheras, —Carnegie ne Ras 
, D.C. Papers o of Sane for Evolution, at Cold Spring Harbor, 
panieuae 24. Pls. 22 and figs. 13. 1905. 
