134 ATKINSON— TWIN HYBRIDS. 



inch pots in May, and from these set out in the garden in June. Of 

 the 75-100 seedhngs of each hybrid type of the reciprocal cross, 50 

 were transplanted to the garden. A few (12-15) of the parent 

 pycnocarpa were grown for comparison, and about 150 of the parent 

 lamarckiana. The object in growing them as biennials was to obtain 

 the well-developed autumnal rosettes. In all of the cultures the 

 rosettes were large, well developed and remarkably uniform except 

 for an occasional mutant from the pycnocarpa type, and a few mu- 

 tants from the parent lamarckiana. 



The F., of the pycnocarpa type (pycno X lam) No. i§j. — The 

 pycnocarpa character, the cutness of the leaves over the basal half, 

 is very pronounced, though it is not so strong as in the parent 

 pycnocarpa. The convexity and crinkledness inherited from la- 

 marckiana is very striking. The width of the leaves is greater than 

 in the lamarckiana type. The type of rosette is well represented 

 in the F^ of the reciprocal cross (PI. I, fig. i). 



The Fo rosettes of the pycnocarpa type of the reciprocal cross 

 {lam X pycno) were identical with those of the pycno X lani cross, 

 and no photograph was made, but the form of the rosette of this type 

 is shown in PI. I, fig. i. 



While this hybrid type has been called the pycnocarpa type, the 

 rosettes really show more of the lamarckiana character than they 

 do of the pycnocarpa character. If these twin hybrids were to be 

 named now, I should reverse the names because of the preponder- 

 ance of lamarckiana characters in the rosettes of the pycnocarpa 

 type, and the preponderance of pycnocarpa characters in the la- 

 marckiana type. But as all my notes, numbers and marks on the 

 negatives correspond to the names here employed, it does not seem 

 wise to change at this time. In this connection it is of interest to 

 note that the pycnocarpa type throws occasional mutants. The 

 rosettes of the mutants which have thus far appeared are of two 

 types. One appears to be a dwarf of the true lamarckiana. The 

 other has very narrow, furrowed leaves, resembling in some respects 

 the lamarckiana type of these twins, but is much smaller and the 

 leaf edge rather strongly toothed the entire length. The pxcno- 

 carpa type of twin, in addition to presenting a predominance of 



