4 | \? Lut/., Triploid Mutants in Ocnothera. 



was the individual first thought to have been (). In fa X ^- Lainar- 

 ckiitiHi (7), nowhere does he inform the reader that the 2 1-chromosome 

 plant was derived from guarded fertilizations. No mention is made 

 of the number of individuals grown in this culture of 0. lata X 0. 

 U't/as, nor docs he state the number of plants in which he counted 

 21 chromosomes. It is not even asserted that a guarded pollination 

 of O. lata X O- yiyrts had ever been made. The only information 

 which the reader is given concerning the pedigree of the 2 1-chro- 

 mosome plant is included in the following statement (13, p. 180): 



"The plants from which these studies were made were grown 

 at Wood's Hole, Mass., in 1905 and 1906 from seeds of de Vries." 



One is left to infer from this statement that the crosses were 

 made by de Vries, but it is possible that this is not the meaning 

 which he intended to convey. 



De Vries, in 1908, described a culture of 0. lata X 0. giyas 

 as follows (6, p. 759): 



,,Im Sommer 1907 erzog ich 133 Pflanzen, welch e schon im 

 Juli deutlich zwei Typen zeigten. 68 Exemplare zeigten gleichzeitig 

 die Merkmale beider Eltern, wahrend die ubrigen 65 keine Spur 

 von /rtfa-Eigenschaften verrieten, sondern genau den Bastarden von 

 0. LamarcJciana X 0. gigas glichen." 



Three small cultures of O. lata X O.gigns have been grown at Cold 

 Spring Harbor 23 ), and the majority of the offspring have been found 

 to belong to the two types described by de Vries, although, as 

 previously reported (20), several other forms appeared in the Cold 

 Spring Harbor cultures which were quite distinct from either of the 

 two more common types. I devoted almost two years to the careful 

 study of the relation of somatic chromosome number to vegetative 

 character in the offspring of O. lata X O. gigas. During the 

 growing season of 1908 (from the germination of the first seedling 

 leaves early in the spring until late in October after the plants 

 were killed by frost), attention was directed almost exclusively to 

 the study of the vegetative characters of these and other primroses 



23) The two cultures of 1907 and 1908 were of separate parentage, but each 

 of the two lots was derived from a single female pollinated by a single male. In 

 referring to the hybrids of the 1908 culture reported in February. 1909 (20) C4ates 

 says (14): 



"Whether these hybrids all had the same individual O. lata plant as mother 

 is not stated," etc. 



My mistaken usage of the term 'extracted latas' for first generation hybrid 

 ul'l's|iring was doubtless misleading, but he has curiously overlooked the following 

 statement contained in the short note in which these hybrids were reported (20), 

 and t.i which he refers: 



"The hybrids were the progeny of a single pair of parents; the pistil parent 

 in this case being a mutant which arose from a culture of pure-bred Lamarckiana, 

 and the pollen parent a pure-bred gigas." 



