Dictyosphaeria cavernosa (Forssk.) Børgesen
Family
Siphonocladaceae
Synonyms
Ulva cavernosa Forssk., Valonia favulosa C. Agardh, Dictyosphaeria favulosa (C. Agardh) Decne. ex Endl.
Vernacular Names
| English | Green bubble weed (Australia). |
Geographical Distributions
Dictyosphaeria cavernosa is widely spread in tropical and subtropical seas all over the world. In Southeast Asia, this alga is recorded in all countries except Cambodia, Vietnam and Brunei Darussalam.
Description
Dictyosphaeria cavernosa is a sessile thallus, dark green, hollow, measuring 2-5(-12) cm in diametre, nearly spherical, irregularly lobed or partly collapsed and occasionally concrescent. It is sometimes rupturing, irregularly saucer-shaped, and reaches a diametre of 30 cm in deep water. It is attached by irregularly elongated (rhizoidal) cells. The surface of thallus consists of a single layer of large angular vegetative cells, which are 0.1-1(-4.5) mm in diametre. The connecting tenacular cells are numerous, measuring 35-50 µm x 60-65 µm, lenticular, with simple or bifurcate haptera and often with fringed distal margins.
The life cycle is diplohaplontic and isomorphic. The sporophytes are with 4 flagella zoospores. The male and female gametophytes produce biflagellate isogametes.
Ecology / Cultivation
Dictyosphaeria cavernosa is commonly found on rocks and reefs in intertidal zone, where it is however often poorly developed. A little lower down on the shore, it reaches full size, and it has also been recorded at depths of up to 55 m. The composition and texture of the rocky substrate greatly influence communities of this alga. It often grows on white, porous shell remains, which reflect light and have a high water-holding capacity. The alga can penetrate this substrate and then grow in semi-protected niches.
Line Drawing / Photograph
References
- Plant Resources of South-East Asia No.15(1): Cryptogams: Algae.
