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Taxon
Cladacanthella scabra (Lamarck, 1816)
Nomenclature
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Family: PlumulariidaeGenus: Cladacanthella
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Synonyms: 1
SUMMARY
Hydrorhiza a knot of thin, tough tubes.
Colony consisting of up to 15 monosiphonic stems to 300 mm high, greater length of stems unbranched, distal stem region a branched canopy with up to three orders of branching into verticels, a deep hinge joint above fork on each branch. Branch internodes variable in length, becoming shorter distally, nodes collar-shaped, deep, internodes of younger branches bearing four hydrocladia, older branches bearing up to 10; apices of some branches with two or three thick, upwardly directed apophysal spines without hydrocladia. Perisarc of stems and branches very thick, thinning a little distally.
Hydrocladial apophyses very long, upwardly directed with a strongly oblique distal node and deep creases in perisarc; hydrocladia alternate, short, on front of branch, close-set on younger branches, directed forward and slightly reflexed, older branches with whorls of up to six hydrocladia. Hydrocladial internodes short, nodes strongly oblique, narrow, one to four intranodal septa, one passing into hydrocladium midway along adcauline wall of hydrotheca, another at base of lateral nematotheca, one, hook-shaped, be low posterior margin of hydrotheca and one, not always present, behind node.
Hydrotheca small, occupying almost entire internode, tubiform, abcauline wall sinuous, curving upward to margin, adcauline wall convex, immersed in hydrocladium, margin broadly lobate, excavated back to internode.
Nematothecae large, all of similar shape, bithalamic, movable, basal chamber long, one mesial inferior on prominence of internode at base of hydrotheca, cup deep, adcauline side s lightly foreshortened, adpressed into curve of abcauline hydrothecal wall or standing erect; lateral nematotheca inserted without pedicel below hydrothecal margin, basal chamber shorter than that of mesial, cup level with hydrothecal margin; two or three cauline nematothecae associated with apophysis - one axillar, facing inwards to branch, another about halfway along apophysis, the third (if present) at base of distal apophysal node.
Colour: Stem and branches of live colonies grey-brown, fading to lighter brown, hydrocladia grey-white.