Distribution and habitat of Eulalia speciosa (Poaceae) newly recorded from Hyogo Prefecture, western Japan

Abstract

Eulalia speciosa, a rare plant in the Poaceae of the warm-temperate zone, has been considered to be one of the 'Tokai floral elements' by various authors. In 1994, however, E. speciosa was found in the eastern Harima region, Hyogo Prefecture, Kinki district, western Japan. An intensive survey followed revealed that about 30 localities of E. speciosa populations exist in this region. A distribution map of E. speciosa in the Japanese archipelago was presented on the basis of herbarium specimens, including those from the new localities. In the eastern Harima region, E. speciosa grows in the Miscanthus-type dry grasslands formed on bald hills and on irrigation pond embankments. Nearly all localities are geologically restricted to areas with rhyolite pyroclastic rocks and lavas. The establishment of bald hills caused by fires and cutting, together with a dry climate and unique geology, may be the main factors supporting the E. speciosa populations in this region. Additionally, the establishment of a large number of small grasslands on irrigation pond embankments seems to have provided suitable refugia for E. speciosa through recent loss of grassland habitats caused by reforestation and progressive succession.