BIOTIC Species Information for Delesseria sanguinea
Researched byDr Harvey Tyler-Walters Data supplied byMarLIN
Refereed byDr Joanna Jones
Scientific nameDelesseria sanguinea Common nameSea beech
MCS CodeZM594 Recent SynonymsNone

PhylumRhodophycota Subphylum
Superclass ClassRhodophyceae
SubclassFlorideophycidae OrderCeramiales
Suborder FamilyDelesseriaceae
GenusDelesseria Speciessanguinea

Additional InformationYoung specimens may be confused with Apoglossum ruscifolium (q.v.) or Hypoglossum hypoglossoides (q.v.) although these species lack the conspicuous lateral veins of Delesseria sanguinea. Wave eroded (battered) specimens may resemble Phycodrys rubens. However, true Phycodrys rubens has lobed or toothed blades and reproductive structures are born on mature blades.
Taxonomy References Maggs & Hommersand, 1993, Hiscock, 1986(b), Dickinson, 1963, Kain & Bates, 1993,
General Biology
Growth formTurf
Feeding methodPhotoautotroph
Mobility/MovementPermanent attachment
Environmental positionEpifloral
Typical food typesNot relevant HabitAttached
BioturbatorNot relevant FlexibilityHigh (>45 degrees)
FragilityIntermediate SizeMedium-large(21-50cm)
Height Growth RateUp to 30 cm
Adult dispersal potentialNone DependencyIndependent
General Biology Additional InformationDelesseria sanguinea is perennial and exhibits a complex life cycle. This species exhibits a strong seasonal pattern of growth and reproduction. New blades appear in February and grow to full size by May -June becoming increasing battered or torn and the lamina are reduced to midribs by December (Maggs & Hommersand, 1993). Blade weight is maximal in midsummer, growth dropping in June and July and becoming zero in August (Kain, 1984). Small new blades may be formed in darkness, reserves translocated from assimilates stored in the frond ribs and stipes which persist in winter (Luning, 1990; Maggs & Hommersand, 1993). Kain (1987) suggested that new blade growth may result from an increase in irradiance and hence inhibition of reproduction (e.g. due to removal of Laminarian plants from a kelp canopy) which may explain occasional crop of new blades noted in summer. Kain (1987) also suggested that the normal seasonal trigger for new blade production was temperature, probably when temperatures fell to 13 deg C or below. Morphology, salinity and temperature tolerances differ between North Sea and Baltic populations. In the Baltic specimens are smaller than British specimens, with thinner blades. Temperature and salinity tolerances are probably genetically determined (Rietema, 1993).
Biology References Maggs & Hommersand, 1993, Lüning, 1990, Hiscock, 1986(b), Dickinson, 1963, Rietema, 1993, Bold & Wynne, 1978, Kain, 1982, Kain, 1987, Kain & Norton, 1990,
Distribution and Habitat
Distribution in Britain & IrelandRecorded from all coasts of the British Isles. However, records from the east coasts are sparse, presumably due to the lack of suitable substrata.
Global distributionRecorded from the north eastern coast of Iceland to the Russian coast near Murmansk. Its southern limit is in Sables d'Olonnes, northern France. It is also found in the Baltic.
Biogeographic rangeNot researched Depth rangeLower eulittoral to at least 30 m
MigratoryNon-migratory / Resident   
Distribution Additional Information

Substratum preferencesBedrock
Large to very large boulders
Small boulders
Physiographic preferencesStrait / sound
Ria / Voe
Enclosed coast / Embayment
Biological zoneLower Eulittoral
Upper Infralittoral
Sublittoral Fringe
Wave exposureExtremely Exposed
Very Exposed
Moderately Exposed
Tidal stream strength/Water flowModerately Strong (1-3 kn)
Weak (<1 kn)
SalinityVariable (18-40 psu)
Full (30-40 psu)
Reduced (18-30 psu)
Habitat Preferences Additional Information
Distribution References Norton, 1985, Maggs & Hommersand, 1993, Lüning, 1990, South & Tittley, 1986, Dickinson, 1963, Rietema, 1993, Kain, 1987, Molenaar & Breeman, 1997, JNCC, 1999, Picton & Costello, 1998, Hardy & Guiry, 2003,
Reproduction/Life History
Reproductive typeOogamous
Developmental mechanismSpores (sexual / asexual)
Reproductive SeasonSee additional information Reproductive LocationInsufficient information
Reproductive frequencyAnnual episodic Regeneration potential No
Life span6-10 years Age at reproductive maturityInsufficient information
Generation timeInsufficient information FecundityInsufficient information
Egg/propagule sizeInsufficient information Fertilization type
Larval/Juvenile dispersal potentialInsufficient information Larval settlement periodNot relevant
Duration of larval stageNot relevant   
Reproduction Preferences Additional InformationDickinson (1963) suggested a life span of 5-6 years but Kain (1984) estimated that 1 in 20 specimens may attain 9 - 16 years of age. All reproductive structures in Delesseria sanguinea are born on the mibribs. The typical life cycle of members of the Ceramiales is summarised as follows:
  • Male haploid gametophytes release male gametes (spermatia) from spermatangia on male bladelets.
  • Female haploid gametophytes produce the female gamete, the carpogonium on female bladelets
  • After fusion (fertilization) the carposporophyte develops, enclosed in a stalked cystocarp and releases diploid carpospores.
  • Carpospores develop into the tetrasporophyte, a diploid sporophyte stage.
  • The sporophyte develops tetrasporangia in which haploid tetraspores are formed by meiosis.
  • The tetraspores develop into gametophytes.
The gametophyte and sporophyte stages in the order Ceramiales are isomorphic (Bold & Wynne, 1978). The onset of sexual reproduction is stimulated by daylength, Delesseria sanguinea is a short-day plant sensitive to a night-break (Kain, 1991; Kain, 1996]. The male bladelets and spermatangia develop between September - December in the Isle of Man. (Kain, 1993). Cystocarps and tetrasporangia appear from December to March and the carpospores and tetraspores are first released in December. Female carpogonia develop 2-3 months before the carposporophytes (c. September). Tetrasporangia form in response to shorter day length (<10h days) than male and female gametangia (Kain, 1996). In culture male bladelets were stimulated by 11-12h days, spermatangia taking 4 weeks to develop. Spermatangia were inhibited by increased day length in culture. Kain (1987) suggested that the southern limit of Delesseria sanguinea may be determined by winter temperatures. Studies in Roscoff and Helgoland showed similar seasonality; new blades formed in April - June at Roscoff, males plants in October - December, cystocarps and tetrasporangia in October - December, the last cystocarps found in April. Juvenile recruitment occurred between February and April/June in both Roscoff and Helgoland (Molenaar & Breeman, 1997).
Reproduction References Maggs & Hommersand, 1993, Lüning, 1990, Dickinson, 1963, Bold & Wynne, 1978, Kain, 1982, Kain, 1987, Kain, 1991, Molenaar & Breeman, 1997, Norton, 1992, Kain, 1996, Kain & Bates, 1993,
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