A fragile, coralline alga often confused with Lithothamnion corallioides. Its form is very variable but commonly resembles stag's horns of irregular diameter. Older specimens become somewhat erect with nodular branches and are reminiscent of red 'coral'. Unattached plants may reach about 7 cm in diameter with branches up to 6 mm in diameter and mauvish brown in colour. The surface can be smooth or flaky.Maerl is a generic name for certain coralline algae that grow unattached on the sea bed. No crustose plants of Phymatolithon calcareum have been recorded from the British Isles.

Unattached branched and calcareous thalli to 6 mm diameter. Attached thalli unknown in the British Isles but have been recorded elsewhere. Lithothamnion corallioides.

Bay of Fundy

Dutch Exclusive Economic Zone, European waters (ERMS scope), Gulf of Maine, Irish Exclusive economic Zone, Mediterranean Sea, North West Atlantic, United Kingdom Exclusive Economic Zone

British Isles: common and widely distributed on southern and western coasts. Europe: Mediterranean, Atlantic coast of Spain and France, Baltic Sea and Norway. Further afield: Arctic Sea and Canary Islands.

Red colour results from the dominance of the pigments phycoerythrin and phycocyanin; this masks the other pigments, chlorophyll a (no chlorophyll b), beta-caratene and a number of unique xanthophylls.

Depth range based on 42 specimens in 1 taxon.

Environmental ranges
  Depth range (m): 4.11 - 27.43

Graphical representation

Depth range (m): 4.11 - 27.43
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Depth range based on 12 specimens in 1 taxon.
Water temperature and chemistry ranges based on 1 sample.

Environmental ranges
  Depth range (m): 1.5 - 32
  Temperature range (°C): 11.785 - 11.785
  Nitrate (umol/L): 5.058 - 5.058
  Salinity (PPS): 35.243 - 35.243
  Oxygen (ml/l): 6.141 - 6.141
  Phosphate (umol/l): 0.380 - 0.380
  Silicate (umol/l): 2.891 - 2.891

Graphical representation

Depth range (m): 1.5 - 32
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

 Typically found in less than 20 m depth on sand, mud or gravel substrata in areas that are protected from strong wave action but have moderate to high water flow. The crustose form is very rare in the British Isles. Usually found as unattached plants forming beds of coralline algal gravel (maerl) in the sublittoral and occasionally lower littoral. Typically found together with Lithothamnion corallioides in the southern British Isles or Lithothamnion glaciale in the northern British Isles.

The unattached plants form maerl beds in the sublittoral in sheltered areas.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Species: 32
Species With Barcodes: 1