palustris.--Androsace vitalliana.


CHAPTER II.
HYBRID PRIMULAS.

The oxlip a hybrid naturally produced between Primula veris and vulgaris.--The
differences in structure and function between the two parent-species.--Effects
of crossing long-styled and short-styled oxlips with one another and with the
two forms of both parent-species.--Character of the offspring from oxlips
artificially self-fertilised and cross-fertilised in a state of nature.--Primula
elatior shown to be a distinct species.--Hybrids between other heterostyled
species of Primula.--Supplementary note on spontaneously produced hybrids in the
genus Verbascum.


CHAPTER III.
HETEROSTYLED DIMORPHIC PLANTS--continued.

Linum grandiflorum, long-styled form utterly sterile with own-form pollen.--
Linum perenne, torsion of the pistils in the long-styled form alone.--Homostyled
species of Linum.--Pulmonaria officinalis, singular difference in self-fertility
between the English and German long-styled plants.--Pulmonaria angustifolia
shown to be a distinct species, long-styled form completely self-sterile.--
Polygonum fagopyrum.--Various other heterostyled genera.--Rubiaceae.--Mitchella
repens, fertility of the flowers in pairs.--Houstonia.--Faramea, remarkable
difference in the pollen-grains of the two forms; torsion of the stamens in the
short-styled form alone; development not as yet perfect.--The heterostyled
structure in the several Rubiaceous genera not due to descent in common.