Callipsygma

Thallus erect, uncalcified, to about 35 cm. tall, consisting of holdfast to 3 cm. across, relatively coarse and generally branched erect axes or stipes to ca. 1.5 cm. diameter but tapering upwards, and younger branches which bear finer complanate branches, thereby producing a dense, somewhat zonate, plumose appearance. Terminal branch systems tend to resemble small (0.5-1.5 cm. long) flabellae, are composed of predominantly dichotomously branched siphons which at times become laterally attached to adjacent siphons to produce essentially monostromatic flabellules, probably of limited growth. Main axes composed of branching siphons of broader diameter; compressed, seemingly darker colored, and almost concealed over part of their length by a covering, or loose cortex, produced by chains of short, appressed, dichotomously branched torulose siphons emanating from main siphons. Siphons contain both chloroplasts and amyloplasts, and at times acicular crystals; walls appears to lack cellulose. Modes of reproduction unknown.

Callipsygma is known only for subtropical sites in southeastern Australia, and Tasmania; it has been collected from heavily shaded pools from ca. -1 to -10m, and dredged at about -30m.