Dicarpidium is a nominally monotypic genus endemic to Australia, belonging to tribe Hermannieae and subfamily Byttneroideae of Malvaceae sensu APG. The original author, F. Mueller describes the plant as being allied to Waltheria in particular. If differs from Waltheria in possessing two carpels, instead of one, in each flower.
The single described species, Dicarpidium monoicum F. Mueller, is a rare shrub of Northern Australia. (F. Mueller refers it to the sandstone tableland of the Gulf of Carpenteria - "Macarthur river and Seven Emu creek" - but APNI specifies a distribution in Western Australia; the ANBG plant distribution mapper agrees with the former.) It is a pink-flowered shrub or tree, with monoecious flowers, and a fruit consisting of two carpels.
Florabase has D. monoicum present in Western Australia, and also lists two further undescribed species from the Kimberley region. The Northern Territory has two undescribed species in Arnhem Land. It is not clear whether the Kimberley and Arnhem Land species are different.
Dicarpidium monoicum F. Mueller
An undershrub, covered on most, if not all, parts by rigid stellate hairs.
The leaves are oblong, about 1 in. long, toothed, plicate and densely hirsute. They are borne on short petioles.
The flowers are small, borne on short pedicels, solitarily or in pairs or triplets in leaf axils. (Bentham refers to a bract and pair of bracteoles, which I take to be reduced leaves and stipules, rather than additional to the leaves.) The male flowers are larger than the female flowers. In both cases both stamens and styles are present, but one or the other is sterile. The calyx is 5-lobed. The petals are oblong-spathulate. There are 5 stamens, very shortly united at the base. The ovary has 2 cells, each with two ovules, and corresponding to the cells 2 distinct, upwards thickening, styles.
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© 2002, 2003, 2010 Stewart R. Hinsley