Het Festuca ovina-complex in Nederland. 3. De smalbladige schapengrassen

After a reply to De Wilde-Duyfjes, who commented on an earlier published treatment of the relatively broad-leaved sheep fescues, the Dutch small-leaved sheep fescues are discussed. Taxonomy and nomenclature of the small-leaved sheep fescues closely related to Festuca ovina is confusing. Until 2005, Dutch literature only recognised two taxa: F. filiformis Pourr. and F. ovina L. In Belgium, Great-Britain and Germany at least four taxa have been recognised: F. ovina subsp. hirtula (Hack. ex Travis) M.J.Wilk. and F. ovina subsp. ophioliticola (Kerguélen) M.J.Wilk. (= F. guestfalica Boenn. ex Reichb), as well as the two taxa already mentioned. In this paper, it is argued that the tetraploid taxa are best considered as subspecies of F. guestfalica Boenn. ex Reichb. and separate from F. ovina. Morphometric analysis of a part of the collection of the herbarium of Naturalis in Leiden (L) and the herbarium of the author revealed that all four taxa can be distiguished in the Netherlands as well. Festuca filiformis is the most common one and occurs on acidic and mostly sandy soils all over the country. Festuca guestfalica subsp. hirtula is quite common on acidic sandy soil of the lateral moraines and blown outs in the central part of the country (Veluwe). Festuca guestfalica subsp. guestfalica occurs in South Limburg, where it grows on heavy metal soils in the floodplain of the River Geul. The subspecies is extremely rare and in such decline there that it has locally become almost extinct. Recently, however, it was found on chalk outcrops in South Limburg and at a single locality in the Veluwe. Possibly, the subspecies may occur at other localities outside its known distribution area as well. Two collections from Apeldoorn, collected in the 19th century, probably belong to Festuca ovina. No recent collections of this species are known.