226 



THE AMERICAN NATURALIST [Vol. LIII 



The sister plant, no. 12, wliieli proved to be homozygous 

 for carmine, behaved differently, giving rise to a progeny 

 of plants which were very variable in height.^ A number 

 of these plants appeared to possess the Mammoth habit 

 of indeterminate growth and gave no evidence of blossom- 

 ing. On October 26, 1916, the heights of the plants, all 

 of which had blossomed except those of Mammoth habit 

 of growth, were as follows: 



TABLE III. 



Number in class 12 (blossomed) 16 (blossomed) 3 (Mammoth) 



The shortest plants in this progeny were first to blos- 

 som and produce'd an average of only 20 to 25 leaves, in- 

 cluding the first bald sucker. Other plants of intermedi- 

 ate heights blossomed considerably later and produced an 

 average of 35 to 40 leaves, including the first bald sucker. 

 Those plants of Mammoth habit of growth which showed 

 no indications of blossoming had produced considerably 

 more than 40 leaves. 



Two of these Mammoth plants, nos. 12 (a) and 12 (b), 

 each seven feet in height, were transplanted in the green- 

 house October 21 without cutting them back. Both plants 

 1)1os>()iium1 December 8, producing carmine blossoms, 

 i'lant IK). I'J (a) had produced 70 to 75 leaves, not includ- 

 ing many Iji act-like leaves below the flowerhead. Plant 

 no. 12 (b) produced 60 to 65 leaves, including all small 

 ones below the flowerhead. 



In addition to these two Mammoth plants the seed of 

 several of the taller sister plants, nos. 12 (c) and 12 (d), 

 in class 2, which had blossomed late, producing 35 to 40 

 leaves, were saved separately. The progenies of all were 

 grown in the field at Arlington Farm, Va., in 1917. A 



4 The leaves of the mother plant no. 12 were characterized by coarse, 

 thick, broad and rounded blades abruptly contracted at the base to a long, 

 almost naked or slightly winged petiole. This striking tj-pe of leaf has re- 



12 (a), 12 (b), 12 (c) and^l2^(d), descending from this mother plant. 



