Class: Charophyceae or stoneworts

Charaphyta or charophyceae are freshwater algae, which usually grow attached to some substrate by root-like structures called rhizoids. Unlike some of the earlier algae, they can be fairly 'large' in size, with their shoots forming nodes from which whorls of side branches originate. Sexually they are pretty advanced, producing reproductive structures similiar to that found in some of the mosses..it has an egg protected by secondary sexual cells.. thus some speculate they may be the ancestor of the moss line. Like all of the greens, they carry chorophyll a and b... they don't always appear the typical green you might associate with these pigments.

from: http://vis-pc.plantbio.ohiou.edu/algaeimage/pages/Chara.html

On a more technical note.... The most differentiating aspect from the other 2 classes is that the nuclear membrane disappears before metaphase. and the spindle persists until after partitioning is complete In some species furrowing occurs and in others a phragmoplast and cell plate is formed Species produce a dormant zygote that undergoes zygotic meiosis so that all multicellular stages are haploid; in higher speices there is a clear case of oogamy = gametes differentiate into large eggs and smaller sperm. Flagellated species are inserted laterally and and attach to a multilayered structure of microtubules so that the cells are asymmetric.

Coleochaetales

The fifteen species of Coleochaetales have gained attention recently because they are implicated as the closest living relatives of the Plantae. Some species have parenchymatous growth, nurturing of the zygotes, and a fossil record of an appropriate age, all of which strengthen the implication Coleochaete is a small genus of filamentous or parenchymatous green algae. The ca. five species occur commonly in freshwater environments worldwide, where they usually are found as epiphytes on aquatic plants. Coleochaete, and the allied genus Chaetosphaeridium, are thought to be the closest living algal relatives of the stoneworts

Individual vegetative cells of Coleochaete species are usually 5-20 µm in diameter and 1-4 times as long as broad, with a conspicuous cell wall. The cells contain a single plastid that occupies most of the cell periphery and contains at least one pyrenoid. (Chara), brittleworts (Nitella), and land plants. The cells are organized into branched filaments that, together, produce a plant body less than 2 mm in diameter. This plant body is prostrate on, or embedded in, the substrate, with no plastid-bearing "erect" filaments extending from the substrate plane. In some species, the filaments are laterally compressed, forming a circular thallus with no apparent gaps between cells. Cultured plants that do not become fixed to a substrate may form spherical balls of cells.