Monocotyledon

Allium crenulatum, an onion, with a typical monocot perianth and parallel leaf venation

Comparison of a monocot (grass) sprouting (left) with a dicot (right), showing hypogeal development in which the cotyledon remains invisible within the seed, underground. The visible part is the first true leaf produced from the meristem; the cotyledon itself remains within the seed.

Slice of onion, showing parallel veins in cross section

Monocotyledons (/ˌmɒnəˌkɒtəˈliːdən, -ˌkɒtˈliː-/), commonly referred to as monocots, (Lilianae sensu Chase & Reveal) are flowering plants (angiosperms) whose seeds typically contain only one embryonic leaf, or cotyledon. They constitute one of the major groups into which the flowering plants have traditionally been divided, the rest of the flowering plants having two cotyledons and therefore classified as dicotyledons, or dicots. However, molecular phylogenetic research has shown that while the monocots form a monophyletic group or clade (comprising all the descendants of a common ancestor), the dicots do not. Monocots have almost always been recognized as a group, but with various taxonomic ranks and under several different names. The APG III system of 2009 recognises a clade called "monocots" but does not assign it to a taxonomic rank.

单词	Monocotyledonous Plants
释义	Monocotyledonous Plants 英语百科 Monocotyledon Monocotyledons (/ˌmɒnəˌkɒtəˈliːdən, -ˌkɒtˈliː-/), commonly referred to as monocots, (Lilianae sensu Chase & Reveal) are flowering plants (angiosperms) whose seeds typically contain only one embryonic leaf, or cotyledon. They constitute one of the major groups into which the flowering plants have traditionally been divided, the rest of the flowering plants having two cotyledons and therefore classified as dicotyledons, or dicots. However, molecular phylogenetic research has shown that while the monocots form a monophyletic group or clade (comprising all the descendants of a common ancestor), the dicots do not. Monocots have almost always been recognized as a group, but with various taxonomic ranks and under several different names. The APG III system of 2009 recognises a clade called "monocots" but does not assign it to a taxonomic rank.
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Monocotyledonous Plants

Monocotyledon