Arabidopsis umezawana (Brassicaceae), a New Species from Mt. Rishirizan, Rishiri Island, Hokkaido, Northern Japan

Abstract

A new species, Arabidopsis umezawana Kadota, is here described from Rishiri Island, Hokkaido, northern Japan. Arabidopsis umezawana is distinguished from A. kamchatica subsp. kamchatica by having plantlets at axils and inflorescences, uneven, adaxial surface of cauline leaves, suborbicular seeds with wings ca. 0.3 mm wide, non-nerved valves and the absence of radical leaves at anthesis; from A. halleri subsp. gemmifera by having annual or biennial habit, suborbicular, winged seeds and the absence of radical leaves at anthesis. This new species is restricted to the alpine zone of Mt. Rishirizan and grows under Betula ermanii - Alnus maximowiczii scrub and in alpine meadow. A new combination, Arabidopsis gemmifera, is also propsed.