ARACHNOIDEUM L., 1753
Synonyms :
Sempervivum sanguineum Jeanbernat ex Timbal-Lagrave (1876)
Distribution : European mountains (Alps, Appennini, Pyrenees, Cordillera Cantabrica, Corsica); usually calcifuge.
Description (according to IHSP, 2003) :
Rosette densely tufted, compact, subglobose, densely leaved, 0.5 - 2 cm in diameter.
Leaves oblanceolate to oblong-obovate, subacute to apiculate, incurved, 5 - 12 x 3 - 5 mm, usually with brown or red tip, ± covered with a cobwebby veil of long, flexuous, interwoven hairs from the tip, upper part and along margins, margins not ciliate.
Flowering branches 4 – 15 cm, leaves red-tipped with apical tuft of arachnoid hairs.
Inflorescence compact, flattish, 5- to 15-flowered.
FIowers 8- to 10-merous, 1 - 1.5 cm in diameter, sepals connate for up to 3 mm, obtuse, very fleshy, 4 - 5 mm, petals broadly lanceolate or rhombic, apiculate, narrowed at the base, carinate, bright reddish-pink with greenish keel, 7 - 10 x ± 3 mm.
An extremely variable species with regard to size and hairiness of the rosettes. The subspecies are rather ill-defined, showing some geographical basis but a considerable overlap (Zonneveld 1981). Generally they are separable on a combination of characters. Hybridization occurs very frequently with other sempervivums whenever occuring together.
See also Alan C. Smith, The Genus Sempervivum and Jovibarba, 1980
Two subspecies :
Sempervivum arachnoideum ssp. arachnoideum
Sempervivum arachnoideum ssp. tomentosum (C.B.Lehmann & Schnittspahn) Schinz & Thellung, 1923