Monocotyledon
Acorales
Alismatales
Arales
Arecales
Asparagales
Bromeliales
Commelinales
Cyperales
Dioscoreales
Hydatellales
Iridales
Juncales
Liliales
Orchidales
Pandanales
Poales
Typhales
Zingiberales
</table>
Monocotyledons or
monocots are a group of
flowering plants usually ranked as a class and once called the Monocotyledoneae. This taxonomic grouping is now named
Liliopsida after the
type genus,
Lilium. Flowering plants not included in the Liliopsida are
dicotyledons or dicots. These two broad groups are distinguished by the number of
cotyledons, or embryonic leaves, in their
seeds: dicots have two, and monocots have one.
The monocots are considered to form a
monophyletic group which evolved from an early dicot. The earliest fossils presumed to be monocot remains date from the
early Cretaceous period. The largest modern monocot family is the
Orchidaceae (orchids), plants which have specialized in insect pollination. For this reason many species of orchids produce very complex flower structures. The second largest and perhaps more notable family, the
Poaceae (true grasses), have evolved in another direction, becoming highly specialized for wind pollination. Grasses produce small, generally inconspicuous flowers.
In addition to having but one embryonic cotyledon, the monocots are set apart within the flowering plants by a number of other specializations. See
how to distinguish a monocot from a dicot.
Monocot Taxonomy
The APG II Classification System, developed by the Angiosperm Phylogeny Group, recognizes ten orders of monocots and two families not yet assigned to any order, and divides these among the Base Monocots and Commelinids:
- Base Monocots
- Commelinids
References
- Chase MW, Soltis DE, Soltis PS, Rudall PJ, Fay MF, Hahn WJ, Sullivan S, Joseph J, Molvray M, Kores PJ, Givnish TJ, Sytsma KJ, Pires JC (2000). Higher-level systematics of the monocotyledons: An assessment of current knowledge and a new classification. In: Wilson KL, Morrison DA, eds. Systematics and evolution of monocots.. CSIRO, Melbourne. 3-16. ISBN 0643064370