Calamagrostis purpurea – ein lange übersehenes boreales element, neu für die flora von österreich

Calamagrostis purpurea, a presumably relict boreal wetland grass with a wide distribution
in Eurasia, is presented here as new for the flora of Austria. The currently known distribution
of this species in Central Europe and its ecological preferences are summarized. After revision of
herbarium vouchers, C. purpurea has to be excluded from the flora of Hungary, as the single known
population on a ski slope in the Börzsöny Mts. turned out to be the single currently known population
of C. villosa in Hungary. Putative occurrences of C. purpurea (published under C. phragmitoides)
from the Waldviertel (Lower Austria), documented in phytosociological relevés that were
overlooked in the floristic literature, are erroneous. Herbarium vouchers of Austrian material of
C. purpurea exist from Piburger See (Ötztal, North Tyrol) and Lunzer Obersee (Ybbstaler Alpen,
Lower Austria), where the species was confirmed during field work in 2016 and 2017. Whereas the
1975 collection from Piburger See was correctly identified during a herbarium revision in 2012, the
occurrence at Lunzer Obersee was already suspected during a floristic mapping excursion in 1992.
A misidentified voucher was collected at Lunzer Obersee in 1907, thus being the oldest record of
C. purpurea for Austria. All revised specimens from both localities are enumerated and discussed in
the context of published floristic and vegetation ecological data. The population size and ecological
conditions of the two Austrian populations, as well as the possibility of a relict status vs. postglacial
migration, are discussed. The category “endangered” (EN) is suggested for the future Austrian Red
Data Book. An identification key for the three most frequently misidentified species of Austrian
Calamagrostis (C. purpurea, C. canescens and C. villosa) is presented as an Appendix.