Osmunda regalis
Osmunda regalis L.
Osmundaceae – Royal Fern family
Conservation status. Critically Endangered [CR B2ab(ii,iii)]. BDA.
Morphology and biology. Perennial herb with short, stout rhizome. Leaves not wintering, more or less leathery, up to 80(150) cm, bipinnate; outer ones sterile, inner ones with sterile basal part and fertile apical paniculate part covered by numerous large sporangia. Sporangia globular or pyriform, short-stalked, arranged in dense groups. Spores numerous, large, almost round, green (with chlorophyll). Sporophylls formation IV–V, spores ripening V.
Habitats and populations. Hygrophyte. In open marshy places or localities which are slightly drying out, beside irrigation canals, also in shady damp places in forests of Alnus glutinosa; on diluvial, slightly to very acid fluvisols. Three fragmented populations are known, comprising some dozens to some hundreds of individuals, growing in groups.
Distribution in Bulgaria. Valley of Struma River (southern) – in the valley of Stroumeshnitsa river near Kolarovo and Gabrene villages; up to 300 m alt.
General distribution. Sub-cosmopolitan, with very wide but disjunct distribution. Europe (mainly W), Azores, Africa, Madagascar, Mascarene Islands, Asia, east N America, Mexico, C America and the Antilles, S America.
Threats. Climate aridisation; limited distribution of the species; low potential for reproduction; habitat loss and degradation as a consequence of improvement activities and drainage; ploughing; grazing; trampling; tree felling; fires; invasion of competitors.
Conservation measures taken. Protected species according to the national Biodiversity Act. One of the populations (near Kolarovo village) is in Topilishte Protected Site. Species localities lie within a site of the European ecological network Natura 2000 in Bulgaria.
Conservation measures needed. Implementation of the elaborated action plan for protection of the species. Inclusion of the population near Gabrene village, as well as the second population near Kolarovo village in protected areas. Population monitoring. Habitat maintenance and conservation. Preserving of genetic material in genome resource bank.
References. Stojanov & Achtarov 1951; Achtarov & Jordanov 1963; Velev 1984; Webb 1993.
Author: Daniella Ivanova
