Isoetes hawaiiensis: A Previously Undescribed Quillwort from Hawaii

Abstract

The pteridophytes of Hawaii have received relatively little attention from botanists during the past half-century. However, intensive recent studies in the islands have revealed a number of previously undescribed species, including the quillwort named here. Quillworts have been found in Hawaii several times since early this century. Between 25 September and 17 October 1917, Charles N. Forbes discovered Isoetes from pools atop Mt. Eke on the island of Maui (Forbes 682. M. BISH). Forbes did not recognize his collection to be Isoetes. It was not until 17 October 1977, when F. R. Warshauer collected Isoetes from the east slope of Mauna Kea on the island of Hawaii (Warshauer & McEldowney 1500 BISH), that Hawaiian botanists realized there was a native quillwort in the flora. Robert W. Hobdy again discovered Isoetes in pools on the summit of Mt. Eke on 23 October 1980 (Hobdy 931 BISH), and he collected it once more from the same site on 21 October 1982 (Hobdy 1705-1710 BISH). Study of these specimens and three later collections from Mt. Eke (Taylor 5332, 5658 MIL and Palmer 672 BISH) indicates that these Hawaiian quillwort acquisitions represent a previously undescribed species of Isoetes.