Rhodophyta, Red Algae
Lithophyllum frondosum (Dufour) Furnari Cormaci & Alongi
Rhodophyta, Order: Corallinales; Family: Corallinaceae. A recent investigation reveals that the Mediteranean Pseudolithophyllum expansum species is - in fact - Lithophyllum frondosum (Furnari et al., 1996.(
Lithophyllum, means ‘stone-loving’ and frondosum, means ‘leafy’, which describes the structure of the thallus, which seems covered by foliage.
The Lithophyllum frondosum is a calcified and flat alga, hard as rock to touch. However, it easily breaks upon careless
handling or when dislocated from a wall. The colony creates round thalli, arranged one atop the other, generally resembling an arrangement of roses.
The colony can reach 20 cm. A single thallus is usually smaller than 5 cm in diameter and 1-2 mm thick.
The Lithophyllum frondosum is chalky pink, sometimes edging towards purple.
The alga is characterized by its colony shape, which resembles a rose, and by its habitat - hidden regions in the ocean depth.
The Lithophyllum frondosum grows in places that are never exposed: in the inner, lowest edge of a notch created by waves, and in underwater caves.
Biology and reproduction
The Lithophyllum frondosum has a three-stage life cycle. Apparently, it is not eaten by herbivores due to its rigid thallus.
Seasonality and distribution
The alga is perennial, and the thallus seems to live for several
years, although this has not been investigated in this region. The species is common in the north-eastern region of the Atlantic Ocean, and some claim that it is a Lessepsian species that entered the region from the Red Sea (the Indian Ocean).
Extensive studies to catalogue the calcifying algae of the Eastern Mediterranean have not yet been done, since specialized knowledge is required for this task. Many species are identified according to photographs using electron- microscopy. In many cases, the calcium must first be melted using acid. Other species reported in the area include:
Lithophyllum byssoides (Lamarck) Foslie
Lithophyllum incrustans Philippi.