Rock clover

(Trifolium saxatile)

Distribution/habitat

The rock clover is an endemic species of the Western to the mid-Central Alps. In North Tyrol, populations are known in Obernbergertal and in inner Ötztal. Due to its uncommonness, the species counts among the botanical rarities of Ötztal. The rock clover flourishes in gravel bed fields, in scree fields and in moraines of glacier forefields.

Description/characteristics

The rock clover is one of the short-lived species and, depending on the location conditions, is annual to biennial. It forms 10 to 15 cm high, mostly trailing sprouts. Its foliage leaves are triform, no more than 1 cm long and notably covered with silken hair. At the end of the sprout branching, 1-3 flower heads are formed, which are enveloped by enlarged stipules. The sepals are densely covered in hair and larger than the unremarkable, white to pink petals. The rock clover forms loose carpets, which can reach diameters up to half a metre (see photo).

Special features

As opposed to other species, the rock clover is not very competitive. It thus only occurs in open, gappy vegetation and cannot survive long-term in compact turf.

Endangerment/protection

The populations of rock clover in Austria are rated as endangered. The rock clover is also a species of the Fauna-Flora-Habitats Directive, Appendix II and thus benefits from special protection.

Literature

Dellinger, A. & Berger, A. (2009): Vergesellschaftung, Habitatsspezifität und pflanzensoziologische Bewertung der Vorkommen von Trifolium saxatile im Schalfbachtal, Ötztaler Alpen, Tirol. Verhandlungen der Zoologisch-Botanischen Gesellschaft Österreichs, 146: 125–138.