(ENOTHERA ]^IUT. LA'I'A AND (E. MUT. SEMILATA. 533 
foliage of lata. All these plants had the small flowers 
of OR. biennis. The OR. biennis lata mutant again had 
15 chromosomes, though normal biennis contains 14, the 
fundamental number in the genus QAiothera. The lata 
mutant is shown in Text-fig. 3 (p. 534), while Text-fig. 4 
(p. 535) shows the rubrinervis type for comparison. 
Another lata type of equal interest to the last appeared 
in the F 2 of OR. mut. rubricalyx x . gr an di flora. 
This series of hybrids is described elsewhere. Two lata 
plants occurred in one Fg culture numbering 56 plants, but 
only one of them (60 . 1 . 20) came to maturity. They were 
essentially plants with lata foliage and habit, together with 
the remarkable red pigmentation of rubricalyx. The 
plant which matured produced flowers with an abundance of 
pollen, and developed long stout capsules, unlike the typical 
lata, which is almost completely male-sterile and whose 
capsules are short and contain few seeds. In some unknown 
way this sterility had been largely overcome. It is not clear 
whether the presence of great quantities of anthocyanin, 
which was obviously inherited from the rubricalyx grand- 
parent, exerted any effect. This plant had again 15 
chromosomes, though in both mut. rubricalyx and 
Q], gran diflora the number is 14. The behaviour of 
the chromosomes in this plant will be described in detail. 
From these facts we are justified in concluding that plants 
having the foliage and habit of lata or semilata, even 
when these are combined with other characters such as small 
flowers or red pigmentation inherited from their ancestors, 
have constantly 15 chromosomes. 
Cytological Description. 
Somatic mitoses. 
In the previous section we found that a total of 21 
individuals which in foliage and habit belonged in the lata- 
semilata series of forms, all without exception contained 
