Rhodophyta, Order: Rhodymeniales; Family: Rhodymeniaccae. Etymology
Both the name of the genus (Botryocladia) and that of the species (botryoides) are derived from the algal resemblance to a cluster of grapes. Description
The Botryocladia is one of the most beautiful algae found along our coastline. Its branches are cylindrical, and they dichotomously branch out, ending in smooth, shiny bladders coloured burgundy-red. The effect is that of a small cluster of grapes. The bladders are salivary, losing their volume and shrinking when exposed to the air. Size
The algal length reaches 10 cm, but it is usually smaller and sometimes contains only a small number of vesicles or just one. The size of each vesicle is between 4 and 7 cm. Colour
Botryocladia botryoides boasts a fiery red colour, ranging from dark pink to burgundy red. Special features
The alga features a cluster of burgundy coloured bladders, sometimes solitary and sometimes bunched together by the dozens. Microscopic observation of a bladder section reveals its membrane to be composed of tiny, dark cells. On the inside, one finds onion-shaped ‘bulb-cells’.
Botryocladia botryoides -a section of the thallus with tetraspores (reproductive spores) upon it. Habitat
Botryocladia botryoides are to be found in the subtidal zone, in potholes and in shaded areas. The alga is abundant in the potholes created on abrasion platforms, especially on their uppermost, shaded areas, where it is protected from direct sunlight. It develops mostly on rock surfaces, but also as an epiphyte upon other species. It may be found at a depth of 50 m upon hard substrates. Biology and reproduction
The algal life cycle encompasses three generations: the sexual generation (gametophyte), the haploid generation and the asexual diploid (Sporophyte). Reproductive organs found in the bladder branches are darkly coloured and covered in a light wrap. The sporangium - the cystocarp - is spherical, its cellular membrane partially flattened on one side and upraised on the other. The spherical bladder
Botryocladia botryoides - a sporophyte bearing tetraspores.
elongates when female reproductive cells are evident. Reproduction occurs mainly towards summer’s end. Seasonality and distribution
The alga is prevalent the year round. Botryocladia botryoides appears towards summer. Due to the hidden habitat, they are difficult to harvest and may be more predominant than realized. The alga is to be found in the Mediterranean and the warmer regions of the Atlantic Ocean. Additional species
Botryocladia boergesenii J. Feldmann Botryocladia chiajeana (Meneghini) Kylin Botryocladia pseudodichotoma (Farlow) Kylin
Another name for Botryocladia botryoides is Botryocladia (Chrysymenia) uvaria (Wulfen) Kylin.