1932 Chromosome numbers in Hemerocallis, with reference to triploidy 257 



clons have been under cultivation. 



Evidence seems to be accumulating to the effect that various 

 plants, ordinarily considered as diploids, are in reality secondary poly- 

 ploids. The case of the wild and cultivated apples may be cited in this 

 respect. In the family Rosaceae the low basic numbers of chromo- 

 somes appear to be 7 and 8, but in the apples the rule is that the 

 somatic number is 34 with a few cultivated clons in which the somatic 

 number is 51. Nabel (1929 a & b ; 1930) has concluded that the haploid 

 number of 17 here seen was developed from a smaller basic number of 

 7 giving a "halved pentaploid origin ". Darlington and Moffett (1930), 

 from a study of the associations of chromosomes in meiosis, conclude 

 that four chromosomes of a basic seven were duplicated and three were 

 triplicated. They find however that 13 seedlings of the triploid apple 

 "Bramley's Seedling ", presumably crossed with a haploid, possess 

 somatic numbers of 38 for two, 39 for one, 40 for three, 41 for four, 43 

 for one, 46 for one, and 47 for one and on this basis it appears that the 

 spores and gametes of the triploid which functioned were 21, 22, 23, 24, 

 26, 29 and 30. Darlington and Moffett consider that the slightly 

 greater frequency for 41 (2(17)4-7) is also significant in indicating a 

 basic number of 7. 



Various reports similar to the above seem to indicate that the 

 numbers of chromosomes in the functional spores of polyploids do not 

 tend to involve numbers lower than that which is haploid. It also 

 seems that this holds for the cases of assumed secondary polyploids, as 

 for the apples cited above. There are, however, during sporogenesis 

 distributions of low numbers to many nuclei which abort. The stages 

 of polyploidy seem to progress more readily than to regress. Yet it is 

 possible that extended and persistent efforts to secure seedlings of 

 polyploids in daylilies may sometime give a functioning of spores with 

 such a low number as 6, with attendant genetic results of value in 

 breeding. 



In respect to the haploid number of 11 the genus Hemerocallis is an 

 anomaly in the Liliaceae, for of the numerous genera of this family a 

 diploid number of 22 chromosomes is characteristic only for this genus. 

 According to the summary compiled by Gaiser (1930) the haploid num- 

 bers characteristic of large genera of the Lily Family are principally 4, 

 6, 7, 8, 9 and 12. Of these the numbers 7 and 9 do not conform to 

 simple or complete duplication of more elementary sets. The num- 

 ber 5 is reported for the species Disporum Hookeri. The number 10 

 is found in certain species of Calochortus but for others the numbers 7 



