alba flowers intermediate in structure between the
perfect and cleistogamic ones. According to M. Boisduval, an Italian species, V.
Ruppii, never bears in France "des fleurs bien apparentes, ce qui ne l'empeche
pas de fructifier."
It is interesting to observe the gradation in the abortion of the parts in the
cleistogamic flowers of the several foregoing species. It appears from the
statements by D. Muller and Von Mohl that in V. mirabilis the calyx does not
remain quite closed; all five stamens are provided with anthers, and some
pollen-grains probably fall out of the cells on the stigma, instead of
protruding their tubes whilst still enclosed, as in the other species. In V.
hirta all five stamens are likewise antheriferous; the petals are not so much
reduced and the pistil not so much modified as in the following species. In V.
nana and elatior only two of the stamens properly bear anthers, but sometimes
one or even two of the others are thus provided. Lastly, in V. canina never more
than two of the stamens, as far as I have seen, bear anthers; the petals are
much more reduced than in V. hirta, and according to D. Muller are sometimes
quite absent.
Oxalis acetosella.
The existence of cleistogamic flowers on this plant was discovered by Michalet.
(8/9. 'Bulletin Soc. Bot. de France' tome 7 1860 page 465.
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