A. S. Horne. 
78 
petal-lobe; and the vertical the diameter of the corolla in milli¬ 
metres. Thus the first W to the left, in the top horizontal column, 
indicates that a plant bearing flowers with corolla-diameter 5 mm. 
and width of petal-lobe 0*5 mm. exists at Wisley. It is clear from 
the diagram that there are large corollas with narrow (cor.-diam. 
14 mm., pet.-lobe 1 mm.) or wide (cor.-diam. 14 mm., pet.-lobe 2 mm.) 
segments; small corollas with narrow (cor.-diam. 7 mm., pet.-lobe 
0'6 mm.) or wide (cor.-diam. 8 mm., pet.-lobe T4 mm.) segments ; 
and corollas of intermediate kinds. It is also evident that the 
corollas of smallest diameter possess the narrowest petal-segments 
(cor.-diam. 5 mm., pet.-lobe 0-5 to 1 mm.). 
Stamens. The stamens exhibit puzzling variability. It seemed 
possible at first to arrange the plants in two sections—one, in which 
the stamens are of equal size, and equal to or exceeding the sepals, 
and, but perhaps with rare exceptions, fertile; the other with 
stamens arranged in two whorls and shorter than the sepals. In 
the second group the stamens varied in size in different plants. 
They were all less than one-third of the length of the sepals in some 
individuals; in others, the stamens of one whorl were one-third and 
those of the second whorl one-half the sepal-length ; in others, one 
whorl was less than one-third and the second greater than two- 
thirds of the sepal-length, and so on. The stamens, in this section, 
proved almost invariably sterile. 
A number of individuals were subsequently found with 
characters that seemed to pertain to both sections, for the flowers 
on the same plant were not all alike with regard to their stamens. 
I found flowers with all the stamens short and flowers with stamens 
of unequal height, varying between the shortest and longest type in 
the same inflorescence. The inflorescence of another individual 
possessed two flowers having ten stamens of equal height (largest 
type) and, on another branch, one flower with four long stamens and 
six sterile short ones—the latter in two series. The anthers of the 
long fertile stamens are of a reddish colour before dehiscence but 
the colour changes to dark-brown after the pollen is shed. The 
anthers of the shortest sterile stamens are of a pale yellowish colour 
and wither without becoming red; those of the longer, sterile, but 
better developed stamens, may redden but do not shed pollen. 
Among the flowers of the intermediate series, the long stamens 
closely resemble those of fertile flowers, but they very frequently 
remain red after the styles have developed and do not shed pollen 
or, if at all, very rarely. 
