Description
Species of Duma are shrubs, 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. Staminate flowers have eight stamens and a rudimentary or missing pistil; pistillate flowers have staminodes. The fruit is in the form of an ovoid or three-angled achene, which is smooth and shiny.[4]
Taxonomy
The genus Duma was created by Tanja M. Schuster in 2011 for some species previously placed in Muehlenbeckia, but which were shown by molecular phylogenetic studies to form a distinct clade. The name is derived from the Latin for "thorn-bush".[4] Duma is placed in the tribe Polygoneae of the subfamily Polygonoideae. Within the tribe, it is most closely related to the genera Atraphaxis and Polygonum, forming the so-called "DAP clade", and is not so closely related to Muehlenbeckia.[2]
{{Polygoneae cladogram}}Species
{{As of|2019|March}}, three species were accepted by Plants of the World Online:- 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
1. ^1 2 {{Citation |last1=Schuster |first1=Tanja M. |last2=Reveal |first2=James L. |last3=Bayly |first3=Michael J. |last4=Kron |first4=Kathleen A. |date=2015 |title=An updated molecular phylogeny of Polygonoideae (Polygonaceae): Relationships of Oxygonum, Pteroxygonum, and Rumex, and a new circumscription of Koenigia |journal=Taxon |volume=64 |issue=6 |pages=1188–1208 |doi=10.12705/646.5 |lastauthoramp=yes }}
2. ^1 2 {{Citation |last1=Schuster |first1=T.M. |last2=Wilson |first2=K.L. |last3=Kron |first3=K.A. |date=2011 |title=Phylogenetic relationships of Muehlenbeckia, Fallopia and Reynoutria (Polygonaceae) investigated with chloroplast and nuclear sequence data |journal=International Journal of Plant Sciences |volume=172 |pages=1053–1066 |doi=10.1086/661293 |jstor=10.1086/661293 |lastauthoramp=yes }}
}}{{taxonbar|from1=Q18340651}} 2 : Polygonoideae|Polygonaceae genera