Class consisting of roughly 170,000 species of angiosperms. Often referred to as the dicotyledons - dicots for short. Dicots are not now recognized as a natural phylogenetic group. A subset of the dicots are a natural group and are referred to as Eudicots.
Vegetative Characteristics: Dicots are diverse in habit, with half of all the species being more or less woody-stemmed - a reflection of the usual presence of a vascular cambium in the class. Annuals, biennials, vines, epiphytes, aquatics, parasites, and saprotrophs are also well represented in dicots. Vascular bundles of the stem are usually borne in a ring that encloses the pith. Vessel elements present except in some putatively primitive woody or aquatic families. Most dicots have a primary root system derived from the radicle, although some have an adventitious root system commonly seen in the class of monocots. Cotyledons are usually 2, seldom 1, 3, or 4. Leaves are mostly net-veined.
Reproductive Characteristics: Floral parts - especially the perianth - are arranged in a spiral or more commonly in definite numbers: typically borne in sets of 5, less often 4, seldom 3. Pollen is typically 3-pored (or derived) except in some putatively primitive dicot families.