The Morton Arboretum's Naturalist Certificate Program
	Back to Courses

Local Flora I: Spring Woodlands | Grasslands | | Glossary: Plant Parts | Flowers | Leaves Monocots | Liliaceae | Other Monocot spp. | | Dicots | Ranunculaceae | Other Dicot spp.
Featured family: Ranunculaceae Buttercup Family	Dicotyledons - Class Magnoliopsida Definition: Plants which produce on the germination of the seed, two "seed-leaves" or cotyledons.
	The dicots outnumber the monocots in Illinois. The dicots have vascular bundles in a ring in the stem, a cambium, have flower parts in 4's and 5's and have two cotyledons. Dicots have many different growth forms as a result of the vascular cambium and range from tiny herbaceous plants like Drosera species (sundews), to climbing vines and bushy shrubs, to giant trees like the oaks.
	Dicots differ from monocots by having branching veins in the leaves (net venation). Leaf arrangement is variable, often opposite or alternate. Stipules often present. Underground structures are various, but frequently a primary root or tap root is present.
	Flowers are borne either from axils or terminally and may be solitary or arranged in various types of inflorescences, including cymes, corymbs, umbels, spikes, racemes, panicles or heads. Some flowers are borne directly on the trunk (e.g. Ficus). Flowers can be perfect or imperfect with plants being monoecious or dioecious.
	The perianth is often well differentiated into calyx and corolla. The predominant number of perianth parts per flower is 4 or 5 (rarely 3). These perianth parts may be free, united at the base, or united into a tube. The flowers are radially symmetrical (actinomorphic) or zygomorphic. Ovary position is variable.
	All fruit types are found within the dicots.

Edna Davion Department of Botany, The Field Museum Chicago, IL 60605-2496 E-mail: edavion@fieldmuseum.org

Photographs by Jane and John Balaban Skokie, Illinois North Branch Restoration Project Leaf and acorn photos by Patrick Leacock.