These organisms have a bushy appearance, frequently emerging from a fibrous or bulbous anchoring structure. Their stalk is notably calcified, and the branches extend more or less in a single plane above it. Internally, their structure consists of filamentous, coenocytic strands that run closely parallel and become rigid at the joints. In the medulla of the segments, these filaments are loosely branched and bear specialized clusters of smaller branchlets on the sides. In some cases, the medullary filaments are sealed off by thickened walls at the points of branching and at the base of the gametophores. The upper parts of these plants are a muted green, while the lower regions take on a whitish-green color.