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This species is accepted, and its native range is E. Ethiopia.

[KBu]

Thulin, M. 2009. New species of Euphorbia (Euphorbiaceae) from eastern Ethiopia. Kew Bulletin 64: 469. DOI: https://doi.org/10.1007/s12225-009-9138-y

Conservation
This species may well have a wider range, but in view of its very restricted known distribution and the small number of plants seen, it should be regarded as Critically Endangered CR D1. However, at present there are no particular threats to the type locality.
Distribution
Euphorbia suborbicularis is known only from the type locality in the south-eastern part of the Somali National Regional State (previously Harerge Region) of Ethiopia. Only a few plants of this species were seen in the area.
Ecology
Open Acacia-Commiphora bushland in a rocky gully on gypsum; 300 m. Other woody species in the immediate surroundings include Boswellia ogadensis, Commiphora oddurensis, Euphorbia ogadenensis, E. polyantha and Jatropha rivae.
Morphology General Habit
Soft-wooded subshrub, c. 0.5 m tall, with stems much-branched and ascending to form tangled masses; stems fleshy, up to 1 cm in diameter, terete, smooth, greyish white with a waxy surface, minutely puberulous; leaf scars prominent, becoming black
Morphology Leaves
Leaves alternate, mostly well separated; petiole 5 – 15 mm long, flattened, minutely puberulous; blade suborbicular, 25 – 45 mm long and wide, ± distinctly cordate at the base, rounded to shallowly emarginate at the apex, glabrous above, minutely puberulous below; stipules represented by minute dark glands
Morphology Reproductive morphology Inflorescences
Inflorescence a (1 –) 3-rayed pseudumbel at tips of branchlets, often with additional axillary cymes below, subtended by a whorl of leaf-like bracts; rays 2.5 – 6 cm long, dichasial, slender, often arching, pale green; axillary cymes up to 10 cm long, slender, arching, pale green, becoming grey, persistent; paired bracts sessile, reniform-semicircular, up to 14 × 20 mm, truncate to cordate at the base and ± overlapping, broadly rounded and shortly apiculate at the apex, glabrous above, minutely puberulous below
Morphology Reproductive morphology Inflorescences Cyathia
Cyathia bisexual, on c. 1 mm long pubescent stipe; involucre cup-shaped, c. 2 × 2 mm, densely pubescent with spreading hairs; glands 4 or 5, sessile, transversely elliptic, spreading, c. 0.5 × 1 mm, subentire with the outer margin deflexed and minutely crenulate, green, glabrous above, minutely pubescent below; involucral lobes fan-shaped, c. 1 mm long and wide, with laciniate margin
Morphology Reproductive morphology Seeds
Seeds c. 3 × 2 mm, flattened, with raphe on ventral side, pale yellow with scattered whitish tubercles, acute, greyish white at the tip; caruncle white, hairy, easily falling off
Note
This is a very distinctive species with somewhat uncertain affinities. Probably it is related to Euphorbia polyantha Pax in sect. EremophytonBoiss., a fairly widespread species in Kenya, Tanzania, Somalia and south-eastern Ethiopia, and also found in the type locality of E. suborbicularis. However, the new species differs markedly from E. polyantha in, for example, its fleshy (not distinctly woody), greyish white (not finally reddish brown) stems, suborbicular and cordate (not broadly obovate and cuneate) leaves with 5 – 15 mm (not 2 – 5 mm) long petiole, stipitate (not sessile) cyathia, and pubescent (not glabrous) involucre, ovary, styles and filaments. Also the bracts tend to be larger (up to 14 mm versus up to 10 mm long) and the rays longer (up to 6 cm versus up to 3 cm long) in E. suborbicularis than in E. polyantha.
sex Female
Female flowers: ovary pubescent, exserted on pubescent recurved pedicel; styles c. 2 mm long, spreading, joined at the base, with distinctly 2-fid tips, densely pubescent with spreading hairs. Capsule exserted c. 2 mm from involucre on ± recurved pedicel, broadly ellipsoidal, c. 4.5 × 4 mm, greenish with reddish base, densely pubescent with spreading hairs
sex Male
Male flowers several; bracteoles linear with fimbriate tips; pedicels c. 2 mm long; filaments c. 0.6 mm long, pubescent; anther lobes yellow, sessile, ovoid, c. 0.3 mm long
Type
Ethiopia, Somali National Regional State, Harerge, 34 km from Gode along road to Kelafo, Thulin, Kaariye & Wilhelmi 11302 (holotypus ETH; isotypi K, UPS).
Vernacular
Ciin (Somali, at the type locality). This name is used also for various other species of Euphorbia in Somali, such as E. cameronii, E. consobrina, E. nubica and E. gossypina (Carter 1993).

Native to:

Ethiopia

Euphorbia suborbicularis Thulin appears in other Kew resources:

First published in Kew Bull. 64: 469 (2009)

Accepted by

  • Govaerts, R.H.A. (2011). World checklist of selected plant families published update Facilitated by the Trustees of the Royal Botanic Gardens, Kew.
  • Yang, Y., Riina, R., Morawetz, J.J., Haevermans, T., Aubriot, X. & Berry, P.E. (2012). Molecular phylogenetics and classification of Euphorbia subgenus Chamaesyce (Euphorbiaceae) Taxon 61: 764-789.

Kew Backbone Distributions
The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

Kew Bulletin
Kew Bulletin
http://creativecommons.org/licenses/by-nc-sa/3.0

Kew Names and Taxonomic Backbone
The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0