his primary divisions of the plant kingdom, which included flowering
plants possessing seeds enclosed in capsules, in contradistinction to
his Gymnospermae, or flowering plants with achenial or schizo-carpic
fruits--the whole fruit or each of its pieces being here regarded as
a seed and naked. The term and its antonym were maintained by Linnaeus
with the same sense, but with restricted application, in the names of
the orders of his class Didynamia. Its use with any approach to its
modern scope only became possible after Robert Brown had established
in 1827 the existence of truly naked seeds in the Cycadeae and
Coniferae, entitling them to be correctly called Gymnosperms. From
that time onwards, so long as these Gymnosperms were, as was usual,
reckoned as dicotyledonous flowering plants, the term Angiosperm was
used antithetically by botanical writers, but with varying limitation,
as a group-name for other dicotyledonous plants. The advent in 1851
of Hofmeister's brilliant discovery of the changes proceeding in the
embryo-sac of flowering plants, and his determination of the correct
relationships of these with the Cryptogamia, fixed the true position
of Gymnosperms as a class distinct from Dicotyledons, and the
term Angiosperm then gradually came to be accepted as the suitable
designation for the whole of the flowering plants other than
Gymnosperms, and as including therefore the classes of Dicotyledons
and Monocotyledons. This is the sense in which the term is nowadays
received and in which it is used here.

[v.02 p.0010]

The trend of the evolution of the plant kingdom has been in the
direction of the establishment of a vegetation of fixed habit and
adapted to the vicissitudes of a life on land, and the Angiosperms are
the highest expression of this evolution and constitute the dominant