Euphorbiaceae
Euphorbia

Euphorbia rivae Pax

First published in Annuario Reale Ist. Bot. Roma 6: 186 (1897)
This species is accepted
The native range of this species is Ethiopia to Kenya. It is a tuberous geophyte and grows primarily in the desert or dry shrubland biome.

Descriptions

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Conservation
Predicted extinction risk: not threatened. Confidence: confident
[AERP]

Euphorbiaceae, A. R.-Smith. Flora of Tropical East Africa. 1987

Morphology General Habit
Glabrous perennial herb with a thick tuberous rootstock to ± 12 × 4 cm. giving rise to several woody underground stems to ± 5 cm. long, which branch at ground-level; branches prostrate and leafy to 15 cm. long, or occasionally more floriferous and erect to 5 cm. high.
Morphology Leaves
Leaves broadly ovate to subcircular, to 17 × 13 mm., base rounded and obscurely oblique, apex rounded, margin entire, undersurface often tinged red; petiole to 1 mm. long; stipules broadly triangular to 0.8 × 0.6 mm., margin deeply toothed, sometimes joined at the base.
Morphology Reproductive morphology Inflorescences Cyathia
Cyathia solitary on peduncles to 4 mm. long, terminal and pseudoaxillary, 2 × 2 mm., with cup-shaped involucres; glands 4, transversely elliptic to 1 mm. wide, red with white entire or obscurely 2–3-lobed appendages to 0.75 × 1.5 mm.; involucral lobes triangular, 0.4 mm. long, shortly ciliate.
sex Male
Male flowers:bracteoles laciniate with ciliate apices; stamens 2 mm. long.
Morphology Reproductive morphology Flowers
Female flower:ovary pedicellate; styles 0.75 mm. long, suberect, bifid to halfway, with thickened apices. Male flowers:bracteoles laciniate with ciliate apices; stamens 2 mm. long.
sex Female
Female flower:ovary pedicellate; styles 0.75 mm. long, suberect, bifid to halfway, with thickened apices.
Morphology Reproductive morphology Fruits
Capsule exserted on a reflexed pedicel 5 mm. long, deeply 3-lobed, 2.25 × 2.25 mm.
Morphology Reproductive morphology Seeds
Seeds oblong-conical, 1.5 × 0.8 mm., pinkish buff and shallowly pitted.
Figures
Fig. 78/4, p. 422.
Habitat
Amongst grass in poor, often water-logged soil (black cotton or sandy); 725–1825 m.
Distribution
K4
[FTEA]

Sources

  • Angiosperm Extinction Risk Predictions v1

    • Angiosperm Threat Predictions
    • http://creativecommons.org/licenses/by/4.0

  • Flora of Tropical East Africa

    • Flora of Tropical East Africa
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • Herbarium Catalogue Specimens

    • 'The Herbarium Catalogue, Royal Botanic Gardens, Kew. Published on the Internet http://www.kew.org/herbcat [accessed on Day Month Year]'. Please enter the date on which you consulted the system.
    • Digital Image © Board of Trustees, RBG Kew http://creativecommons.org/licenses/by/3.0/

  • Kew Backbone Distributions

    • The International Plant Names Index and World Checklist of Vascular Plants 2025. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0

  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2025. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0