Diameter of base and disc usually 10-30 mm, exceptionally larger, height to 50 mm.
Base broad and closely adherent, its outline usually ragged due to basal laceration. Column tall and pillar-like in extension, flaring out just below the disc. Cinclides on the distal part of the column usually discernible as small dark spots; acontia are not readily emitted. A loose covering of mucus and dirt is often present on the lower part of the column and a thin layer of true, adherent periderm may also occur. Disc wide, about twice the diameter of the column. The mouth is often long and characteristically held slightly open in a toothless grin.
Tentacles: Long and very graceful in full expansion; they may be hexamerously or irregularly arranged, up to about 200.
Colouration: Ground colour of column buff, dull orange or reddish brown, with a number of pale cream stripes running upwards from the limbus to about the middle. Between the stripes and on the upper part the ground colour is overlaid by a fine freckling of brown or reddish, rather variable in intensity. Disc translucent cream or greyish, each mesenteric insertion being indicated by a fine orange line which is flanked by a pair of opaque cream ones. The marginal region is more or less strongly suffused with bright orange, often enriched by similar colour on the distal parts of the mesenteries glowing through the translucent tissues. A clearly defined pattern of dark markings is always present on the outer part of the disc, amongst the tentacle bases. Lining of actinopharynx orange. Tentacles very pale grey, transparent and diaphanous in extension, typically with three diffuse cream or white bands - at the base, middle, and tip. Each tentacle frequently bears a median pair of faint dusky longitudinal lines. In comparison with other sagartiids this species is remarkably constant in its colouration, such variation that occurs being in intensity and tone of the colour.
Reproduction: Basal laceration is habitual and very frequent.
Nematocysts of acontia: p-mastigophores 38-51 x 4.0-6.0 öm, b-mastigophores 13-30 x 2.0-3.0 öm.
Attached to various hard substrata - rocks, shells, worm tubes, etc. - occasionally on objects buried in mud or sand; often occurs in small groups of asexually produced individuals. An offshore species, occurring down to at least 100 m, but has been recorded on the shore on one occasion.
Frequent around all coasts of the British Isles and western Europe from Scandinavia southward to Biscay, not known from the Mediterranean.
A pretty little anemone which is readily distinguished from S. undatus by its brighter colouration, smaller size and habitual basal laceration, and from Sagartia spp. by its lack of suckers. Unlikely to be misidentified providing the presence of acontia is ascertained.