Noble corals are pink or orange and tree-like with paler tips to the colony's branches. The calcareous colonies may grow to over 25cm in total height, while individual polyps are 0.1cm in diameter. There is no free medusa stage.
The polyps project from star-shaped cavities in the rigid calcareous skeleton. Growth occurs at the tips and on the outside surface, which gradually thickens and which may show concentric rings in section.
Colour and shape variation
Noble corals feed on plankton and resemble hard corals. They occur in cool temperate waters usually in caves and under overhangs. They are very slow-growing: large colonies may be over 100 years old. A permit is required to collect these animals. 
The following species are considered synonyms of Stylaster nobilis:
- Allopora explanata Kent, 1871
- Allopora nobilis Kent, 1871
- Allopora ochracea Qulech, 1884
- http://marinespecies.org/aphia.php?p=taxdetails&id=210735 accessed 15 August 2013
- Branch, G.M., Branch, M.L, Griffiths, C.L. and Beckley, L.E. 2010. Two Oceans: a guide to the marine life of southern Africa ISBN 978-1-77007-772-0
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