8 BOTANICAL GAZETTE [January 



become much smaller than that of the parent species, which latter 

 is given there as 2 . 2 per cent. The transition of one or more unit 

 characters into the inactive condition was considered there as 

 the probable cause of this change, and the same conception 

 may obviously be applied to our present case. 



Although the mutability of O. blandina is thus seen to be very 

 small, it does not follow that it is wholly absent for other mutations 

 than the one mentioned. Casual mutations parallel to those of 

 O. Lamarckiana may be expected to appear from time to time, 

 either in the pure strains or after hybridizations with other, still 

 less mutable, species. This has occurred once in my garden. 

 Among the offspring of a cross between O. blandina and O. Cocke- 

 relli, a species from Colorado, an individual arose in 191 5 which 

 showed the marks of O. lata combined with those of O. Cockerelli, and 

 agreed with the description given in my book (p. 254). It proves 

 that the mutability of O. blandina into lata is not wholly absent. 



The mutation from 0. blandina, 4 specimens of which occurred 

 in my culture of 191 5, was a strikingly new type, quite different 

 from all the mutations produced by O. Lamarckiana and its deriva- 

 tives until now. It was distinguished at once by its linear leaves, 

 which could be seen in the boxes before the young plants were 

 planted out on the beds. The 4 mutants were brought into the 

 glass-covered part of my garden, where 2 of them have flowered. 

 The 2 others remained small, produced stems, but died in the fall 

 before making any flower buds. Of the flowering specimens one 

 was also small and therefore was not used as a seed-bearer, but the 

 other reached about 1 m. in height, was very richly branched, and 

 bore, from July to October, many hundreds of flowers and fruits. 

 All these flowers had the same type, consisting of narrow petals 

 instead of the large cordate ones of the parental form. The petals 

 did not belong to the type called cruciata, inasmuch as they had not 

 the least sign of the sepalody characteristic of O. cruciata and its 

 allies. Their color was uniformly yellow, not differing from that 

 of O. Lamarckiana. The breadth varied from 0.5 to 1.5 cm. for 

 a length of 3 cm. The form was ovate, with some small indenta- 

 tions along the margin, and the tip was narrowed and more or less 

 spirally twisted. This latter mark, which was best visible during 







