Plants are distinguished from animals by various traits: they have cell walls made of cellulose, polyploidy, and they exhibit sedentary growth.
The terms Angiospermae and Gymnospermae were used by Carl Linnaeus in the same sense, albeit with restricted application, in the names of the orders of his class Didynamia.
[2] The terms angiosperms and gymnosperm fundamentally changed meaning in 1827, when Robert Brown determined the existence of truly-naked ovules in the Cycadeae and Coniferae.
[4] In 1851, Hofmeister discovered the changes occurring in the embryo-sac of flowering plants, and determined the correct relationships of these to the Cryptogamia.
[5] In most taxonomies, the flowering plants are treated as a coherent group; the most popular descriptive name has been Angiospermae, with Anthophyta (lit.
The APG system of 1998, and the later 2003[7] and 2009[8] revisions, treat the flowering plants as an unranked clade without a formal Latin name (angiosperms).
A formal classification was published alongside the 2009 revision in which the flowering plants rank as a subclass (Magnoliidae).
Traditionally, the flowering plants are divided into two groups, to which the Cronquist system ascribes the classes Magnoliopsida (from "Magnoliaceae") and Liliopsida (from "Liliaceae").
Other descriptive names allowed by Article 16 of the ICBN include Dicotyledones or Dicotyledoneae, and Monocotyledones or Monocotyledoneae, which have a long history of use.
The remainder includes a paraphyletic grouping of early-branching taxa known collectively as the basal angiosperms, plus the families Ceratophyllaceae and Chloranthaceae.