''Duma'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s in the family

Polygonaceae The Polygonaceae are a Family (biology), family of flowering plants known Common name, informally as the knotweed family or smartweed—buckwheat family in the United States. The Botanical name, name is Basionym, based on the genus ''Polygonum'', ...

, subfamily

Polygonoideae Polygonoideae is a subfamily of plants in the family Polygonaceae. It includes a number of plants that can be highly invasive, such as Japanese knotweed, '' Reynoutria japonica'', and its hybrid with '' R. sachalinensis'', ''R.'' × ''bohemica' ...

. The genus was separated from ''

Muehlenbeckia ''Muehlenbeckia'' or maidenhair is a genus of flowering plants in the family Polygonaceae. It is native to the borders of the Pacific, including South and North America, Papua New Guinea and Australasia. It has been introduced elsewhere, includin ...

'' in 2011. The native range of the genus is Australia.

Description

Species of ''Duma'' are

s, with many flexible branches, whose tips are thornlike. They have white to greyish bark. The leaves are longer than wide, with a very small curved spine at the tip. The flowers are without stalks ( petioles). Plants are

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

. Staminate flowers have eight

stamen The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

s and a rudimentary or missing

pistil Gynoecium (; ; : gynoecia) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl (botany), whorl of a flower; it consists ...

; pistillate flowers have

staminode In botany, a staminode is an often rudimentary, sterile or abortive stamen, which means that it does not produce pollen.Jackson, Benjamin, Daydon; ''A Glossary of Botanic Terms with their Derivation and Accent''; Published by Gerald Duckworth & Co ...

s. The fruit is in the form of an ovoid or three-angled

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple fruit, simple dry fruits, dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and Dehi ...

, which is smooth and shiny.

Taxonomy

The genus ''Duma'' was created by Tanja Schuster in 2011 for some species previously placed in ''

'', but which were shown by

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

studies to form a distinct clade. The name is derived from the Latin for "thorn-bush". ''Duma'' is placed in the tribe Polygoneae of the subfamily

. Within the tribe, it is most closely related to the genera '' Atraphaxis'' and ''

Polygonum ''Polygonum'' is a genus of about 130 species of flowering plants in the buckwheat and knotweed family Polygonaceae. Common names include knotweed and knotgrass (though the common names may refer more broadly to plants from Polygonaceae). In the ...

'', forming the so-called "DAP clade", and is not so closely related to ''Muehlenbeckia''.

Species

, three species were accepted by

Plants of the World Online Plants of the World Online (POWO) is an online taxonomic database published by the Royal Botanic Gardens, Kew. History Following the Convention on Biological Diversity, the Royal Botanic Gardens in Kew launched Plants of the World Online i ...

: *'' Duma coccoloboides'' (J.M.Black) T.M.Schust. (syn. ''Muehlenbeckia coccoloboides'') *'' Duma florulenta'' (Meisn.) T.M.Schust. (syn. ''Muehlenbeckia florulenta'') *'' Duma horrida'' (H.Gross) T.M.Schust. (syn. ''Muehlenbeckia horrida'')

References

{{Taxonbar, from1=Q18340651 Polygonoideae Polygonaceae genera Dioecious plants