Gloiosiphonia capillaris (Hudson) Carmichael

Also known as Sticky Tube Weed.
Description: Mucilaginous but firm, to 350 mm long and 5 mm wide. Arising from a crustose, expanded base probably producing erect axes repeatedly. Major branching irregularly alternate, generally with a shorter opposite branch, becoming pyramidal in outline. Branches narrowing gradually at both ends. Ultimate branches noticeably banded. Plants monoecious, forming sunken but swollen cystocarps. Tetrasporangia formed on crustose plants; terminal, obliquely or irregularly cruciately divided.
Habitat: Growing or rock in pools in the lower intertidal and in the subtidal to 5 m. Generally occurring between April and August, but occasionally found at other times.
Distribution: Widely distributed in the NE Atlantic from Norway and Sweden south to Spain and Portugal. Said to have a south-western distribution in Britain and Ireland, but is widely distributed, if sporadic and genuinely rare. Also known from the N Pacific. Records elsewhere require reassessment.
Similar species: Lomentaria clavellosa which is less mucilaginous, regularly pinnately branched, is generally compressed, and does not have banded laterals.
Photograph: Cornwall © David Fenwick.

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