jnii Lutz, Triploid Mutants in Ociiothera. 



in the immediate future. Since the chromosome numbers of the 

 offspring of the Cold Spring Harbor 21 -chromosome mutants are 

 unknown, these plants, unfortunately, can not be accepted as positive 

 evidence of one sort or another. 



The discovery of 21- and 22-chromosome mutants opens the 

 question of the identity of certain plants first described by Gates 

 as offspring of 0. lata X 0. Lamarcldana (7). He said (p. 83): 



"My garden of 1906 contained fifteen plants from seed of 

 0. lata pollinated by 0. Lamarckiqna, ten of which conformed more 

 or less completely to the characters of the pollen parent and four 

 to the lata type, which is easily distinguished even in the rosette 

 stage. One plant (no. 79), however, differed markedly from either 

 of these forms, and was clearly a 'mosaic' hybrid, /'. e., in some 

 characters it resembled one parent and in some characters the other 

 parent. The petals, however, were considerably larger than those 

 of either parent species, and the sepals showed streaks of red, 

 suggesting the sepals of 0. rubrinervis but much paler. This 

 character, however, is common to all the plants of 0. lata X 0. 

 Lamarcldana having the Lamarcldana characters, and is occasionally 

 seen to a less degree in 0. Lamarcldana itself. The large ovaries 

 and stout hypanthium, the greater pubescence on the young buds, 

 and the broad leaves with their obtuse tips, are all characters of 

 0. lata. But the leaves were scarcely at all crinkled (the more or 

 less complete absence of crinkling being a character of 0. Lamar- 

 cldana which distinguishes it easily from 0. lata), and the general 

 habit of branching and greater luxuriance of growth also correspond 

 with 0. Lamarcldana. This plant is mentioned as showing that 

 segregation of the parental characters is not always complete in 

 this cross, as this individual was fairly intermediate in position 

 between the tw r o parents, though no fractionization of any characters 

 was observed." 



Gates' description of the so-called "'mosaic' hybrid" of this 

 culture so closely resembles the description of the 21-chromosome 

 Cold Spring Harbor mutant that I believe them to be the same 

 thing. While he states that 'the large ovaries and stout hypanthium, 

 the greater pubescence on the young buds, and the broad leaves 

 with their obtuse tips are all characters of (). lata', the first three 

 characters might be stated equally well as descriptive of 0. gigas, 

 and the last as distinctive of certain types of 0. gigas (the linear- 

 leafed form of course being a notable exception). 



Unfortunately, Gates did not state the chromosome number 

 of this plant, and it is probable that it was not ascertained. 



In discussing the chromosome numbers of certain individuals 

 of this culture, he said (p. 97): 



