Subspecies, varieties, forms and cultivars of plants belonging to the Sempervivum globiferum group

Sempervivum globiferum subs. hirtum has been known from the 16th. century having been described by Clusius, and collected by Joachim Burser (1583-1639) in the Radstadter Tauern Alps of Upper Styria. Sempervivum globiferum (syn: Jovibarba globifera) comprises four closely related subspecies, the nominate form (subs. globiferum), Sempervivum globiferum subs. allionii (sym: Jovibarba allionii), Sempervivum globiferum subs. arenarium (syn: Jovibarba arenaria) and Sempervivum globiferum subs. hirtum (syn: Jovibarba hirta). Previously, the epithet "globiferum" was used incorrectly for some species of the genus Sempervivum L. with yellow flowers. However, after unification of the above mentioned four species into one species the epithet "globiferum" has priority. [Jovibarba sobolifera (J. sims) Opiz is the synonym of J. globifera (L.) J. Parn subsp. globifera]. The epithets "soboliferum", "hirtum", "arenarium", and "allionii" have been used in various nomenclatural combinations, at different ranks within different species creating a taxonomic nightmare. The poor taxonomic distinction is supported by the occurrence of intermediate forms. A great amount of within-population variability is common in Sempervivum globiferum, especially in the contact zone of its different subspecies (e.g. West Carpathians).

• Sempervivum globiferum L.: (subsp. globiferum) has rosette-leaves widest above the middle and incurved, giving a closed, globose rosette. The sepals are glabrous.
• Sempervivum globiferum subs. allionii (Jord. & Fourr.) 't Hart & Bleij
• Sempervivum globiferum subs. arenarium (W.D.J.Koch) 't Hart & Bleij: has smaller rosettes, typically about 25 mm diameter, sometimes red-tipped blades.
• Sempervivum globiferum subs. hirtum (L.) 't Hart & Bleij: has rosette-leaves widest at or below the middle, patent or erect forming an open rosette. Leaves with a grey pruina an long marginal cilia. Sepals hairy.