The flowering plants or angiosperms (Angiospermae or Magnoliophyta) are the most diverse group of land plants. The flowering
plants and the gymnosperms are the only extant groups of seed plants. The flowering plants are distinguished from other seed
plants by a series of apomorphies, or derived characteristics.
Eudicots and Eudicotyledons are terms introduced by Doyle & Hotton (1991) to refer to a group of flowering plants that had
been called "tricolpates" or "non-Magnoliid dicots" by previous authors. The term means, literally, "true dicotyledons" as
it contains the majority of plants that have been considered dicotyledons and have typical dicotyledonous characters. The
term "eudicots" has been widely adopted to refer to one of the two largest clades of angiosperms, monocots being the other.
Monocotyledons or monocots are one of two major groups of flowering plants (angiosperms) that are traditionally recognized,
the other being dicotyledons or dicots. Monocot seedlings typically have one cotyledon, in contrast to the two cotyledons
typical of dicots. Monocots have been recognized at various taxonomic ranks, and under various names (see below). The APG
II system recognises a clade called "monocots" but does not assign it to a taxonomic rank.
Orchidaceae, the Orchid family, is the largest family of the flowering plants. Its name is derived from the genus Orchis.
The Royal Botanical Gardens of Kew list 880 genera and nearly 22,000 accepted species, but the exact number is unknown (perhaps
as many as 25,000) because of taxonomic disputes. The number of orchid species equals about four times the number of mammal
species, or more than twice the number of bird species. It also encompasses about 6–11% of all seed plants.
Asparagales is an order of flowering plants. The order has always included the family Asparagaceae, but other families included
in the order have varied markedly between different classifications. No one is sure, but it is supposed that this group of
plants evolved between late and early Cretaceous. But because of the difficult classification of the families it is not entirely
certain when they evolved.
The rosids are a large group of flowering plants, containing about 70,000 species, more than a quarter of all angiosperms.
It is divided into 16 to 20 orders, depending upon circumscription and classification. These orders, in turn, together comprise
about 140 families. The rosids and the asterids are by far the largest groups in the eudicots. Fossil rosids are known from
the Cretaceous period.
