Hedychium (unnamed species) (Marantaceae).--Almost self-sterile without
aid.
Orchideae.--An immense proportion of the species sterile, if insects are
excluded.
LIST OF PLANTS, WHICH WHEN PROTECTED FROM INSECTS ARE EITHER QUITE
FERTILE, OR YIELD MORE THAN HALF THE NUMBER OF SEEDS PRODUCED BY
UNPROTECTED PLANTS.
Passiflora gracilis (Passifloraceae).--Produces many fruits, but these
contain fewer seeds than fruits from intercrossed flowers.
Brassica oleracea (Cruciferae).--Produces many capsules, but these
generally not so rich in seed as those on uncovered plants.
Raphanus sativus (Cruciferae).--Half of a large branching plant was
covered by a net, and was as thickly covered with capsules as the other
and unprotected half; but twenty of the capsules on the latter contained
on an average 3.5 seeds, whilst twenty of the protected capsules
contained only 1.85 seeds, that is, only a little more than half the
number. This plant might perhaps have been more properly included in the
former list.
Iberis umbellata (Cruciferae).--Highly fertile.
Iberis amara.--Highly fertile.
Reseda odorata and lutea (Resedaceae).--Certain individuals completely
self-fertile.
Euryale ferox (Nymphaeaceae).--Professor Caspary informs me that this
plant is highly self-fertile when insects are excluded. He remarks in
the paper before referred to, that his plants (as well as those of the
Victoria regia) produce only one flower at a time; and that as this
species is an annual, and was introduced in 1809, it must have been
self-fertilised for the last fifty-six generations; but Dr.
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