? Eleocharis obtusa
Taxonomy
The specimens in the Kew Herbarium, cited as "E. ovata R. BR." by from 'Java, ZOLLINGER' and in from 'Java' (see also ) are in fact E. obtusa. Origi- nally they belonged to the HOOKER herbarium; they are provided only with the small printed part of a ZoLLiNGER-label "Plantae javanicae cl. ZOLLING- ERO lectae". This supposed ZOLLINGER collection is not represented in any of the other Eleocharis collections I could study, therefore it is very unlikely that the plants were actually collected in Java. E. obtusa is known from the eastern United States, the Pacific region from northern California to British Columbia, and the Hawaiian Islands.
By its annual, cespitose habit, the bifid style, and the biconvex nut E. obtusa is similar to E. geniculata and E. atropurpurea. It belongs in ser. Ovatae characterized by the flat lamelliform style-base, which is here nearly or quite as broad as the nut. In the closely related, and possibly not specifically distinct E. soloniensis (DUBOIS) HARA = E. ovata (ROTH) R. & S. the style-base is much narrower than the nut.
By its annual, cespitose habit, the bifid style, and the biconvex nut E. obtusa is similar to E. geniculata and E. atropurpurea. It belongs in ser. Ovatae characterized by the flat lamelliform style-base, which is here nearly or quite as broad as the nut. In the closely related, and possibly not specifically distinct E. soloniensis (DUBOIS) HARA = E. ovata (ROTH) R. & S. the style-base is much narrower than the nut.