A fertile branch is a reproductive structure like a cone or a flower. An axillary bud may elongate to form a vegetative (sterile) branch, but it may also develop to form a fertile branch. Axillary buds-also called lateral buds-are just immature branches. An axil is the angle formed between the the upper (adaxial) side of the leaf and the stem to which it is attached the word axil comes from the Latin word axilla, meaning 'armpit' (just remember: the axil is the armpit of the leaf!). In axillary branching, lateral branches grow from axillary buds, or buds the develop in the leaf axils. Thus, branching is not caused by division of the shoot apex. In plants with lateral branching, a main stem grows from an apical bud or terminal bud (a region of the shoot tip that includes the apical meristem), and lateral (side) branches are produced from lateral buds, each with its own apical meristem. In this case, a modifier (like 'isotomous' or 'equal') may be used to indicate the relative size of the branches. Terminology note: 'Dichotomous branching' is often used as a synonym for apical branching, encompassing both isotomous (equal) and anisotomous (unequal) types. Unequal apical branching occurs in lycophytes and some extinct groups, like trimerophytes (the stem group to euphyllophytes, the group that includes ferns, horsetails, and seed plants). In other words, pseudomonopodial branching results in a plant that looks like it has a dominant ('main') stem and lateral (side) branches, even though branching is really apical. A plant with pseudomonopodial branching or pseudomonopodial growth mimics the form of a plant with monopodial growth (discussed below). If apical branching is extremely unequal, it may be called pseudomonopodialВ (Greek pseudД“sВ = fake/false). This type of branching is known as anisotomous (Greek anisos = unequal).

Sometimes, apical branching produces branches of unequal size. Dichotomous branching is also seen in some modern plants like the firmosses ( Huperzia, an example is shown below) and whisk ferns ( Psilotum). Dichotomous branching was the earliest type of branching and is seen in some ancient plant sporophytes, like the Silurian to Devonian plant Cooksonia (typically considered an early vascular plant) and the Devonian plant Aglaophyton (a protracheophyte, a branching plant lacking true vascular tissue, shown below). This type of apical branching is often simply called dichotomous (Greek dicho- = in two), but is sometimes called isotomous (Greek isos = equal). In the simplest type of apical branching, the apex divides to produce two equal branches. Finally, root branching is briefly discussed at the end of this page.ДЄpical branching is a type of branching in which the shoot apex divides, usually bifurcating to produce two branches. Next, monopodial and sympodial growth in laterally branching plants will be explained. Topics include apical branching, lateral branching, and adventitious branching. The first sections of this page will cover branching in shoots.

In shoots, lateral branches develop from buds on the surface of the stem lateral roots originate within the root from which they branch. True lateral branching developed in the euphyllophytes (the group including horsetails, ferns, and seed plants, as well as their extinct ancestors and relatives) and takes places via different processes in shoot and root. Apical branching is the more ancient type of branching in both stems and roots it is also structurally similar in stems and roots. Branching of axes can occur apically (at the apex or tip of an axis) or laterally (on the side of an axis). Branching occurs when one axis (root or stem) divides, or when a smaller axis develops on a larger, more dominant axis. The sporophytes of most vascular plants branch within the normal course of their growth and development.

Dichasial cyme