216 Atkinson. 



through them, so that certain characters, or groups of characters, are 

 transmitted entire to one or the other of the Fi segregate hybrids. 

 Examples of this linking or association of characters are as follows: 

 First, habit characters; second, color characters; third, petal char- 

 acters; fourth, broadness and toothedness of rosette leaves; fifth, 

 narrowness and cutness of rosette leaves; sixth, crinkledness, convexity 

 and red veinedness of rosette leaves; seventh, plainness, furrowedness 

 and white veinedness of rosette leaves (in hijhrida pycnella the mid 

 veins of the leaves are often tinged with red). The linked characters 

 are inherited as follows by the two Fi segregates. 



In hybrida pycnella the habit is taken from nutans^ the rosettes 

 take the broadness and toothedness of the leaves from nutans, the 

 furrowedness, repandness, plainness and white veinedness from pycno- 

 carpa (often a trace of red from nutans?); the green stem and green 

 tubercles come from pycnocarpa; width and edge character of stem 

 leaves come from nutans: the size and persistency of the bracts are 

 derived from pycnocarpa; all the petal characters come from pycnocarpa. 

 It appears that these characters are taken in their entirety from one 

 or the other parent as the case may be and fitted like pieces of mosaic 

 into a new form. A co-operation of these parts of diverse origin is 

 secured which results in a very high state of seed production and fer- 

 tility, unsurpassed by either parent. 



In hybrida tortiiosa the rosettes take the narrowness and cutness 

 of the leaves from pycnocarpa, the convexity, crinkledness and red 

 veinedness of the leaves from nutans; the red stem and red tubercles 

 come from nutans: size and caducous character of the bracts come from 

 nutans; all the petal characters come from nutans. The stem leaves 

 take width, convexity and red veinedness from nutans, but take strong 

 toothedness over the base from pycnocarpa, though there are but a few 

 distant coarse teeth. In 1913 when the analysis of characters was first 

 made, tortuosa existed only in the rosette stage. But this Fi segregate 

 hybrid was so interesting in comparison with its counterpart of the total 

 rosette composition of the two parents, that I had provisionally formu- 

 lated an expectation of the vegetative characters of the adult hybrida 

 tortuosa. On the basis of this expectation the adult tortuosa, from the 

 total vegetative characters of the parent adults, would take those char- 

 acters complementary to the ones combined in the mosaic pycnella. 

 Hybrida tortuosa thus on this calculation would have the width and 

 toothed characters of the stem leaves of pycnocarpa, but would inherit 



