Sempervivum arachnoideum

Scientific profile

Sempervivum arachnoideum is a low-growing, evergreen succulent belonging to the stonecrop family (Crassulaceae). The plant forms compact rosettes of fleshy, broad leaves and typically reaches a height of 8 cm. Flowering occurs between July and September. It is adapted to high light levels (Ellenberg light value 9), dry conditions (moisture value 2), acid soils (reaction value 3) and extremely nutrient-poor substrates (nutrient value 1). It shows a preference for cold, alpine or northern temperature regimes (value 3) and experiences low disturbance severity (0.33). The diaspores are very small, with a mean mass of approximately 0.02 mg, and the species associates with arbuscular mycorrhizal fungi. According to the habitats derived from its indicator values, its primary vegetation type is acidic dry grassland, with secondary associations including alpine grassland and extensive meadows. This species was introduced into Great Britain and has become established outside gardens.