Notes. 
164 
DOUBLE-FLOWERED CEANOTHUS.-— A double-flowered 
Rhamnad has, so far as I know, not hitherto been recorded ; at least, 
no such case is mentioned in Dr. Dammer’s recent German translation 
of my Vegetable Teratology, in which numerous additions have been 
made, both by the translator and myself, to the records given in the 
original edition. It may, therefore, be worth mentioning that among 
some garden varieties of Ceanothus that have lately come under my 
observation, there were several ‘ double ’ forms. The mode of doubling 
in each case was similar. Each flower had a calyx of five sepals as 
usual, then five petals of the ordinary, long-stalked, spoon-shape. In 
front of each of these was a similar petal representing the stamen of 
an ordinary flower. Both sets of petals sprang from the outside of 
a thickened annular disc lining the base of the calyx. Within the 
disc there was no pistil, but in its place a tufted mass of imbricating, 
petaline scales arranged around a slightly prolonged axis. 
The arrangement of the outer parts of the flower may be understood 
by the following formula : — 
S S S S S 
P P P P P 
P P P P P 
The inner row of petals thus exactly corresponds in position with 
the stamens of an ordinary flower. Eichler attributes the superposition 
of the stamens to the petals in Rhamnads to the suppression of an 
outer row of stamens, but in no genus of Rhamnaceae is any second 
row of stamens mentioned. An examination of the flowers in question 
leads me to suggest that the petals and stamens are not in this case 
autonomous organs, but that the one is an outgrowth from the other. 
This can only be determined by a more complete investigation of the 
course of development and the study of the anatomy and distribu- 
tion of the vessels than I have been able to make. In any case, the 
‘ doubling’ of the Ceanothus flower is brought about by the petalisation 
of the stamens, the suppression or non-development of the pistil, and 
by the median-prolification of the flower. Whether mites had anything 
to do with the production of these double flowers I am unable to say, 
my testimony is simply to the effect that I did not find any. Indeed, 
Peyritsch’s experiments need to be confirmed by other observers before 
they can be considered as conclusively proving the agency of mites in 
