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Description: |
Dark-green thallus, cylindrical to club-shaped, spongy, scarcely calcified. The Dasycladus vermicularis is a leaf-like, spongy, cylindrical, unbranched alga. It widens from its base and towards its upper, rounded tip. The connection to the substrate is through a vertical rhizoid. A lateral microscopic cross-section of the alga reveals a central axis, around which branches are arranged that split into secondary branches (see illustration). The branch edges form a velvety surface pointed outwards. The alga mostly appears in small groups, but also in larger groups (link). |
| Name History |
Adjective (Latin), worm-shaped, almost cylindrical and bent in places, marked with irregular waves or bent lines (Stearn 1973). |
| Biogeography |
Warm NE Atlantic (Madeira, Canary Is), Mediterranean; Caribbean; Brazil; Japan; Philippines. |
| Life Cycle |
The thallus is constructed as a unit with no lateral walls. Its only reproductive mode is sexual. The cellular nucleus divides by meiosis into several haploid nuclei. The nucleus wander towards tiny cysts created in fertile whorls found across the alga. The cysts are dark and contain nuclei and chloroplasts. The cysts release dozens of mobile, double- flagellate reproductive cells. The alga is dioecious. Two reproductive cells, equal in size, form a zygote that germinates directly into a new thallus. |
| References |
Pérez-Rodriguez, E., Aguilera, J. & Figueroa, F.L. (2003). Tissular localization of coumarins in the green alga Dasycladus vermicularis (Scopoli) Krasser. A photoprotective role?. J. Experimental Botany 384: 1-8.
Pérez-Rodríguez, E., Gómez, I., Karsten, U. & Figueroa, F.L. (1998). Effects of UV radiation on photosynthesis and excretion of UV-absorbing compounds of Dasycladus vermicularis (Dasycladales, Chlorophyta) from southern Spain. Phycologia 37: 379-387, 7 figs, 2 tables.
Ross, C., Küpper, F.C., Vreeland, V., Waite, J.H. & Jacobs, R.S. (2005). Evidence of a latent oxidative burst in relation to wound repair in the giant unicellular chlorophyte Dasycladus vermicularis. Journal of Phycology 41: 531-541.
Ross, C., Vreeland, V., Waite, J.H. & Jacobs, R.S. 2005 (2005). Rapid assembly of a wound plug: stage one of a two-stage wound repair mechanism in the giant unicellular chlorophyte Dasycladus vermicularis (Chlorophyceae). Journal of Phycology 41: 46-54.
Torres, J., Rivera, A., Clark, G. & Roux, S.J. (2008). Participation of extracellular nucleotides in the wound response of Dasycladus vermicularis and Acetabularia acetabulum. Journal of Phycology 44: 1504-1511 |
| Habitat: |
Gregarious in shallow water of tropical to warm-temperate seas, in calm bays, on firm substrata. |
| Type information: |
Basionym: Spongia vermicularis Scopoli |
