Solanum tuberosum (Solanaceae).—Tinzmann says (‘Gardeners’ Chronicle’ 1846 page 183) that some varieties are quite sterile unless fertilised by pollen from another variety.
Primula scotica (Primulaceae).—A non-dimorphic species, which is fertile with its own pollen, but is extremely sterile if insects are excluded. J. Scott in ‘Journal of the Linnean Society Botany’ volume 8 1864 page 119.
Cortusa matthioli (Primulaceae).—Protected plants completely sterile; artificially self-fertilised flowers perfectly fertile. J. Scott ibid. page 84.
Cyclamen persicum (Primulaceae).—During one season several covered-up plants did not produce a single seed.
Borago officinalis (Boraginaceae).—Protected plants produced about half as many seeds as the unprotected.
Salvia tenori (Labiatae).—Quite sterile; but two or three flowers on the summits of three of the spikes, which touched the net when the wind blew, produced a few seeds. This sterility was not due to the injurious effects of the net, for I fertilised five flowers with pollen from an adjoining plant, and these all yielded fine seeds. I removed the net, whilst one little branch still bore a few not completely faded flowers, and these were visited by bees and yielded seeds.
Salvia coccinea.—Some covered-up plants produced a good many fruits, but not, I think, half as many as did the uncovered plants; twenty-eight of the fruits spontaneously produced by the protected plant contained on an average only 1.45 seeds, whilst some artificially self-fertilised fruits on the same plant contained more than twice as many, namely 3.3 seeds.
Bignonia (unnamed species) (Bignoniaceae).—Quite sterile: see my account of self-sterile plants.
Digitalis purpurea (Scrophulariaceae).—Extremely sterile, only a few poor capsules being produced.
Linaria vulgaris (Scrophulariaceae).—Extremely sterile.