Hedenäs, L. 2005. Oncophorus wahlenbergii var. elongatus I. Hagen, an overlooked taxon in northern Europe. – Lindbergia 30: 32-38

Abstract

Oncophorus elongatus (I. Hagen) Hedenäs (Oncophorus wahlenbergii var. elongatus I. Hagen) is a taxon that has been overlooked in northern Europe. The plants are 8‑10 cm high, which is larger than those of O. wahlenbergii Brid., and form much looser tufts or grow singly among other bryophytes. Oncophorus elongatus additionally differs from O. wahlenbergii in its longer stem leaves, (3.7‑) 4.5‑7.2 mm long, which are more spreading than in the latter and more or less flexuose when moist. The leaf bases are also more strongly sheathing and mostly more strongly widened at their shoulder than in O. wahlenbergii, and the costa is broader, 71.5‑124.0 µm wide near its base. The acumen of the inner perichaetial leaves is longer than in O. wahlenbergii, (1.3‑) 1.4‑2.8 times as long as the sheathing part, and the spore capsules are larger and have a smaller length-to-width ratio than in the latter, although there is some overlap between the two. Oncophorus elongatus grows mainly in the subalpine and low‑alpine zones, most frequently in mineral‑poor or sometimes intermediately mineral‑rich mires, or on brook and river shores. It seems to occur primarily in suboceanic areas of the Scandinavian mountain range, reaching coastal areas particularly in northern Norway.