Polysiphonia lanosa

Polysiphonia lanosa
Scientific classification
Domain: Eukaryota
(unranked): Archaeplastida
Division: Rhodophyta]
Class: Florideophyceae
Order: Ceramiales
Family: Rhodomelaceae
Genus: Polysiphonia
Species: P. lanosa
Binomial name
Polysiphonia lanosa
(L.) Tandy

Polysiphonia lanosa (Polysiphonia fastigiata (Roth) Greville) is a common species of the red algae (Rhodophyta) often to be found growing on Ascophyllum nodosum.[1]

Description

The thalli of this species form dense tufts,[1][2] each tuft up to 7.5 cm generally attached by rhizoids to the fronds of Ascophyllum. The erect cylindrical branches divide pseudodichotomously. A transverse section shows an axial cell surrounded by 12 to 24 perixial cells. The axial cell is large and occupies about one third of the diameter of each branch, best seen in transverse section. It is deep brownish red in colour.[1]

Choreocolax polysiphoniae Reinsch is a small parasitic alga which grows in a cushion-like manner to 1 mm in diameter on the branches of P. lanosa.[3]

Habitat

Widespread growing epiphytically on Ascophyllum lanosum wherever it is found and occasionally on other species of Fucus.[1][4]

Reproduction

The life history is a sequence of three phases: gametangial, carposporangial and tetrasporangial. Two of the phases are similar.[5] The plants are dioecious with spermatangial branches produced in tufts at the apices of the branches,[1] The Cystocarps are borne, usually singly.[6]with a narrow ostiole from which carpospores are released. The tetraspores occur in spiral series[1]resulting from a simultaneous division into 4 equal spores. [7]

Distribution

Common around the British Isles and on the shores of Europe from Iceland, Norway to Spain. Also Greenland and Newfoundland to New England.[1]

References

  1. 1 2 3 4 5 6 7 Maggs, C.A. and Hommersand, M.H. 1993, Seaweeds of the British Isles Volume 1 Rhodophyta Part 3A Ceramiales. The Natural History Museum, London ISBN 0-11-310045-0
  2. ↑ Harvey, W.H. 1841. A Manual of the British Algae: London: John van Voorst
  3. ↑ Irvine, L.M.1983. Seaweeds of the British Isles. Volume 1 Rhodophyta Part 2A Cryptonemiales (sensu stricto), Palmariales, Rhodymeniales. British Museum (Natural History) ISBN 0-565-00871-4
  4. ↑ Lewis, J.R. 1964.p.12 The Ecology of Rocky Shores. The English Universities Press Ltd
  5. ↑ Dixon, P.S. 1973. Biology of the Rhodophyta. p. 187. Oliver and Boyd ISBN 0-05-002485-X
  6. ↑ Dickinson, C.I. 1963. British Seaweeds. The Kew Series
  7. ↑ Irvine, L. M. 1983. p.101 Seaweeds of the British Isles Volume 1 Rhodophyta Part 2A Cryptonemiales (sensu stricto) Palmeriales, Rhodymeniales. (British Museum) ISBN 0-565-00871-4
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