Biology:Sesamothamnus rivae
| Sesamothamnus rivae | |
|---|---|
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Scientific classification 
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| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Asterids |
| Order: | Lamiales |
| Family: | Pedaliaceae |
| Genus: | Sesamothamnus |
| Species: | S. rivae
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| Binomial name | |
| Sesamothamnus rivae Engl.[1]
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| Synonyms[1] | |
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Sesamothamnus rivae is a species of flowering plant in the family Pedaliaceae.[1] It is a caudiciform shrub or small tree native to eastern Africa, where it is found in Ethiopia, Kenya, Somalia, and Tanzania.[1] The plant is known for its swollen, water-storing trunk (pachycaul) and is adapted to seasonally dry tropical biomes.[1][2]
Taxonomy
The species was first described by the German botanist Adolf Engler in 1897, based on collections made from eastern Africa.[1] The specific epithet rivae honors the Italian naturalist and explorer Oreste Riva.
Two names have been synonymized with Sesamothamnus rivae:[1]
The genus Sesamothamnus is closely related to Sesamum (the genus that includes sesame), and both belong to the family Pedaliaceae.[1]
Description
Sesamothamnus rivae is a pachycaul shrub or small tree with a disproportionately large, swollen trunk that stores water.[2][5] The trunk can reach up to 30 cm (12 in) in diameter, while the plant attains a height of 2 to 6 m (6.6 to 19.7 ft).[2][5]
The flowers are small, star-shaped, and range in color from white to brownish-white, with a reddish throat.[2][5]
A herbarium specimen collected in Ethiopia's Segen River valley in 1982 describes a tree approximately 6 m (20 ft) high with "salsh orange" characteristics, growing in arid Acacia woodland and riparian Ficus forest.[6]
Distribution and habitat
The species is native to eastern Africa, with a range extending from Ethiopia southward to northern Tanzania.[1] Its confirmed distribution includes Ethiopia, Kenya, Somalia, and Tanzania.[1][7] The plant grows primarily in seasonally dry tropical biomes, including arid woodlands and savannas.[1][6]
Herbarium records from the Muséum national d'Histoire naturelle in Paris document two preserved specimens of the species.[8]
Ecology
Sesamothamnus rivae is deciduous, losing its leaves during the dry winter period and entering a state of vegetative rest.[5]
The flowers are likely pollinated by insects, though specific pollinators have not been documented in published literature.
Uses
The plant is cultivated as an ornamental plant by succulent enthusiasts due to its distinctive caudiciform growth form.[2]
Cultivation
Growing conditions
The plant prefers warm tropical temperatures ranging from 20 to 35 °C (68 to 95 °F), and cannot tolerate temperatures below 15 °C (59 °F) or freezing conditions.[5] In cultivation, it requires protection from frost and should be kept dry during its winter dormancy period.[5]
Soil and water
Well-draining, sandy soils are essential for successful cultivation, as the plant is susceptible to root rot in waterlogged conditions.[5] A cactus or succulent potting mix is recommended.[5] During the active growing season, the plant requires regular watering, but water should be withheld when the plant loses its leaves in winter.[5]
Conservation
As of 2026, Sesamothamnus rivae has not been assessed for the IUCN Red List. The species is known from multiple locations across four countries and does not currently face any documented major threats.[1]
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 "Sesamothamnus rivae Engl.". Royal Botanic Gardens, Kew. https://powo.science.kew.org/taxon/675944-1.
- ↑ 2.0 2.1 2.2 2.3 2.4 "Sesamothamnus rivae (Caudex)". https://www.giromagi.com/it/shop-caudex/sesamothamnus-rivae.
- ↑ "Sesamothamnus erlangeri Engl.". Royal Botanic Gardens, Kew. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:675941-1.
- ↑ "Sesamothamnus smithii Baker ex Stapf". Royal Botanic Gardens, Kew. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:675947-1.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 "Sesamothamnus rivae 6x6cm". https://www.giromagi.com/en/shop/sesamothamnus-rivae/31604.
- ↑ 6.0 6.1 "Herbarium Catalogue: Sesamothamnus rivae". Uppsala University. https://databas.evolutionsmuseet.uu.se/botanik/browserecord.php?-action=browse&-recid=136845.
- ↑ "Sesamothamnus rivae (Tanzania)". 2017-11-12. https://efloraofindia.com/efi/sesamothamnus-rivae/.
- ↑ "Sesamothamnus rivae Engl.". https://science.mnhn.fr/taxon/species/sesamothamnus/rivae?lang=fr_FR.
External links
- Sesamothamnus rivae at Plants of the World Online
Data related to Sesamothamnus rivae at Wikispecies
Wikidata ☰ Q131937358 entry
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