8.3: Monocots vs. Eudicots

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Monocots

Two seedlings. The seedling on the left has a single curled leaf, on the right the seedling has two leaves. — Figure \(\PageIndex{1}\): Monocots like the grass shown on the left produce only one cotyledon (mono- for one, -cot for cotyledons). Eudicots (on right), also called dicots, get their name from having two cotyledons. Cotyledons are the first, fleshy leaves that enveloped the embryo as it grew. Image from Pengo, CC BY-SA 2.5, via Wikimedia Commons.

A Trillium flower with the number of parts in each whorl labeled — Figure \(\PageIndex{2}\): This Trillium is a monocot, which you can tell because it is 3-merous. There are three sepals, three petals, six stamens, and three stigma lobes visible in the gynoecium. Monocots have floral parts in sets of three (3-merous). Photo by Maria Morrow, CC-BY 4.0.

Eudicots

A Clarkia flower that is 4-merous — Figure \(\PageIndex{4}\): Eudicot flowers tend to be 4-merous or 5-merous. The Clarkia flower (first image) is 4-merous. We cannot see the calyx, but there are four petals, 8 stamens, and 4 stigma lobes. The Flax flower (second image) is 5-merous. There are five sepals poking out between the five petals and 5 stamens (with blue anthers!). The number of stigma lobes is not distinguishable in this image. Photos by Maria Morrow, CC-BY 4.0.

A Flax flower that is 5-merous — Figure \(\PageIndex{4}\): Eudicot flowers tend to be 4-merous or 5-merous. The Clarkia flower (first image) is 4-merous. We cannot see the calyx, but there are four petals, 8 stamens, and 4 stigma lobes. The Flax flower (second image) is 5-merous. There are five sepals poking out between the five petals and 5 stamens (with blue anthers!). The number of stigma lobes is not distinguishable in this image. Photos by Maria Morrow, CC-BY 4.0.