Thirty-four heads, each including many flowers, were examined, and
twenty of them had from one to four flowers, whilst fourteen had not a
single flower thus opened. It is therefore clear that some of the
flowers had been visited by insects, while the majority had not; yet
almost all produced capsules.
Linum usitatissimum (Linaceae).--Appears to be quite fertile. H.
Hoffmann 'Botanische Zeitung' 1876 page 566.
Impatiens barbigerum (Balsaminaceae).--The flowers, though excellently
adapted for cross-fertilisation by the bees which freely visit them, set
abundantly under a net.
Impatiens noli-me-tangere (Balsaminaceae).--This species produces
cleistogene and perfect flowers. A plant was covered with a net, and
some perfect flowers, marked with threads, produced eleven spontaneously
self-fertilised capsules, which contained on an average 3.45 seeds. I
neglected to ascertain the number of seeds produced by perfect flowers
exposed to the visits of insects, but I believe it is not greatly in
excess of the above average. Mr. A.W. Bennett has carefully described
the structure of the flowers of I. fulva in 'Journal of the Linnean
Society' volume 13 Bot. 1872 page 147. This latter species is said to be
sterile with its own pollen ('Gardeners' Chronicle' 1868 page 1286), and
if so, it presents a remarkable contrast with I. barbigerum and
noli-me-tangere.
Limnanthes douglasii (Geraniaceae).
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