426 SEMI-CENTENNIAL OF TORREY BOTANICAL CLUB 
This habit and the abundant branching which result in the pro- 
duction of such large numbers of heads presumably give oppor- 
tunity for the development of heads of such ultimate laterals 
as might be suppressed in a less robust growth, as is seen in dwarf 
races. There should be opportunity to observe, in such a race, 
the lowest possible range of flower number for the species. The 
chancefor developmentof partial variabilityis most favorable. The 
observations indicate that this is the case. In TABLE 44 are shown 
the ranges in number per head for all plants studied in this variety. 
The highest flower number per head extends from 31 to 19 and 
there were 40 plants out of 144 that had produced some heads 
with 25 or more flowers. 
TABLE 44 
RANGE OF FLOWER NUMBER PER HEAD FOR ALL PLANTS OF THE VARIETY RED-LEAVED 
TREVISO 
Difference between 
—| maximum and 
| 
Number of -| Maximum flower | енеке Dower — ы маан) 
ж | — | Range Average | average minimum 
I | 31 — 7.0 | 24.0 
I | 30 — 13.0 17-0 
3 | 28 I5-II 13.0 15.0 
7 | 27 13-10 ІІ.4 | 15.6 
II | 26 12—7 IO.I 15.9 
17 | 25 16-9 12.0 | 13.0 
26 24 14-5 10.7 | 13-3 
27 23 I7 11.2 | 11.8 
26 | 22 14-7 10.0 | II.I 
17 | 2I 14-9 II.I | 9.9 
6 | 20 13-10 11.3 | 8.7 
2 | 19 13-ІІ 12.0 | 7.0 
‚ Furthermore, the low numbers range as low as 5 and in every 
class grouped together for a particular high number some plants 
produced one or more heads of eleven or twelve. The plant with 
the highest numberof flowers per head (31) produced heads ranging 
as low as 7. The complete record of data for this plant is given 
in TABLE 4I. 
This variety is characterized by rather wide extremes of 
partial variability and by high values of a and b. 
