Rhodophyta, Order: Ceramiales; Family: Rhodomelaceae.

Etymology

The name Rytiphlaea refers to the characteristic pleats at the end of the thallus. Tinctoria refers to the fact that the alga was used in the past as a source for red dye.

Description

The Rytiphlaea tinctoria has an elongated thallus that resembles flattened branches and branching that resembles a feather. Using a microscope or magnifying glass, the edges of the side branches are seen to be slightly bent.

Size

The alga reaches 12 cm in length, and its branches range between 1-1.5 mm.

Colour

The Rytiphlaea tinctoria is dark reddish-purple sometimes edging towards brownish red or orange.

Special features

The algal reddish colour seeps slightly and colours water or paper, when drying. Through a microscope or magnifying glass, the branches can be seen curling backwards (a useful mean of identification).

Habitat

The alga is submersed in water, and can be found in potholes, tidal pools and shaded locations in the upper regions of the subtidal zone. Often, it is covered with epiphytes, especially Jania. Tikva Edelstein, during her research, found individuals at depths of between twenty-seventy m; however, these seemed smaller and more delicate than the coastal species; also, they did not seep colour when drying.

Biology and reproduction

The Rytiphlaea tinctoria’s thallus contains two types of reproductive organs, sexual and asexual, as well as sterile hair bearing elements. The cystocarps are contained on the dorsal side of bent branches. They are globular or extend to a sharp point. They are very dark red, tending towards black, and measure up to 0.5 mm in diameter, sometimes more. They develop alongside the hairy elements but are larger. The reproductive spores (tetraspores) are located on the inner sides of branches near the edge and are arranged in two parallel rows: 2-8 tetraspores in each row. These are small, dark and easily seen through a magnifying glass.

Seasonality and distribution

The Rytiphlaea tinctoria is found all the year round, especially in summer. Individuals carrying reproductive organs have been reported in summer and autumn.

Additional species

Rytiphlaea tinctoria is the only species reported so far in our region.

 

The Rytiphlaea tinctoria’s red colour was used by the ancient Romans to manufacture red colouring paste.