Stathmostelma welwitschii Britten & Rendle

First published in Trans. Linn. Soc. London, Bot. 4: 28 (1894)
This species is accepted
The native range of this species is Gabon to Ethiopia and Zambia. It is a perennial or tuberous geophyte and grows primarily in the seasonally dry tropical 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]

Goyder, D. J., Gilbert, M. G. & Venter, H. J. T. (2020). Apocynaceae (part 2). In: M. A. García (ed.), Flora Zambesiaca, Vol. 7(3). Royal Botanic Gardens, Kew.

Type
Angola, near Pedras de Guinga, PungoAndongo, Welwitsch 4168 (BM holotype, K, LISU). StathmostelmalaurentianumDewèvre in Bull. Soc. Roy. Bot. Belgique 34(2): 87 (1895).
Morphology General Habit
Perennial herb with 1 to many annual stems arising from a long, slender, vertical, napiform tuber; stems 0.2–1 m long, simple or branched below, erect or ascending, minutely pubescent with short white hairs
Morphology Leaves
Leaves sessile or with petiole to 10 mm long; lamina 7–16 × 0.2–1.2(1.6) cm, linear to lanceolate, acute, base truncate or rounded, minutely pubescent with short, stiff hairs on both upper and lower surfaces
Morphology Reproductive morphology Inflorescences
Inflorescences extra-axillary with 2–7 flowers in an erect umbel, peduncles (4)7–14(20) cm long, the lower inflorescences with markedly longer peduncles than the upper ones, thus raising all the flowers to approximately the same level, erect, minutely pubescent; bracts caducous; pedicels 1.5–4 cm long, minutely pubescent
Morphology Reproductive morphology Flowers Calyx
Sepals 3–6 × 12 mm, lanceolate to ovate, acute, usually tinged red towards tip, pubescent
Morphology Reproductive morphology Flowers Corolla
Corolla rotate or slightly reflexed, yellow, pubescent at least towards tip on outer surface, minutely papillose towards the base within; lobes 9–12 × 6 mm, oblong to obovate, acute, plane
Morphology Reproductive morphology Flowers Gynostegium
Gynostegium with stipe 1 mm long
Morphology Reproductive morphology Flowers Corona
Corona lobes yellow or orange, 4–6 × 2–4 mm, erect, slightly longer than column, appearing concave-cucullate for most of their length but in fact solid except for the proximal and upper margins, apex rounded distally, the inner apical margins produced into a pair of teeth 1–2 mm long and with a rounded or acute tooth arising from the middle of the cavity, glabrous Corona with slender acute tooth in cavity
Morphology Reproductive morphology Flowers Androecium Stamens Anthers
Anther wings 2–3 mm long, curved; anther appendages 1–1.5 mm long, semicircular and inflexed over apex of stylar head
Morphology Reproductive morphology Flowers Gynoecium Style
Stylar head flat
Morphology Reproductive morphology Fruits
Fruiting pedicel not contorted; follicle erect, 5–10 × 0.5–1 cm, fusiform, beaked, not inflated, smooth, densely pubescent
Morphology Reproductive morphology Seeds
Seeds c.5 × 3 mm, ovate with a verrucose disc and a narrow inflated rim.
Recognition
Stathmostelmawelwitschii can be readily distinguished from S. pedunculatum by the more branched growth form and the flowers which are yellow rather than red.
Distribution
Zambia. Also known from Tanzania, D.R. Congo, Angola and Ethiopia.
Ecology
Seasonally waterlogged grassland; 1000–1650 m.
[FZ]

Apocynaceae (part 2), David Goyder, Timothy Harris, Siro Masinde, Ulrich Meve, Johan Venter. Flora of Tropical East Africa, 2012

Morphology General Habit
Perennial herb with 1 to many annual stems arising from a long, slender, vertical, napiform tuber.
Morphology Stem
Stems erect or ascending, 0.2–1 m long, simple or branched below, minutely pubescent with short white hairs
Morphology Leaves
Leaves sessile or with petiole to 10 mm long; lamina linear to lanceolate, 7–16 × 0.2–1.2(–1.6) cm, acute, base truncate or rounded, minutely pubescent with short, stiff hairs on both upper and lower surfaces.
Morphology Reproductive morphology Inflorescences
Inflorescences extra-axillary with 2–7 flowers in an erect umbel.
Morphology Reproductive morphology Inflorescences Peduncles
Peduncles erect, (4–)7–14(–20) cm long, the lower inflorescences with markedly longer peduncles than the upper ones, thus raising all the flowers to approximately the same level, minutely pubescent.
Morphology Reproductive morphology Inflorescences Bracts
Bracts caducous.
Morphology Reproductive morphology Flowers Pedicel
Pedicels 1.5–4 cm long, minutely pubescent Fruiting pedicel not contorted.
Morphology Reproductive morphology Flowers Calyx
Sepals lanceolate to ovate, 3–6 × 1–2 mm, acute, usually tinged red towards tip, pubescent
Morphology Reproductive morphology Flowers Corolla
Corolla yellow, rotate or slightly reflexed, pubescent at least towards tip on outer surface, minutely papillose towards the base within; lobes 9–12 × 6 mm, oblong to obovate, acute, plane
Morphology Reproductive morphology Flowers Gynostegium
Gynostegium with stipe 1 mm long
Morphology Reproductive morphology Flowers Corona
Corona lobes erect, yellow or orange, 4–6 × 2–4 mm, slightly longer than column, appearing concave-cucullate for most of their length but in fact solid except for the proximal and upper margins, apex rounded distally, the inner apical margins produced into a pair of teeth 1–2 mm long and with a rounded or acute tooth arising from the middle of the cavity, glabrous
Morphology Reproductive morphology Flowers Androecium Stamens Anthers
Anther wings 2–3 mm long, curved; anther appendages 1–1.5 mm long, semicircular and inflexed over apex of stylar head; corpusculum black, ovoid to subcylindrical, ± 0.3 × 0.1 mm; translator arms with a membranous, obovate, convex and somewhat contorted proximal part ± 1.6 × 0.6 mm, and a filiform distal part ± 0.6–1 mm long broadening abruptly into a short clasping overlap with the pollinium.
Morphology Reproductive morphology Flowers Pollinia
Pollinia oblong or obovate, ± 1 × 0.3 mm, flattened
Morphology Reproductive morphology Flowers Gynoecium Style
Stylar head flat
Morphology Reproductive morphology Fruits
Follicle erect, fusiform, 5–10 × 0.5–1 cm, beaked, not inflated, smooth, densely pubescent
Morphology Reproductive morphology Seeds
Seeds ± 5 × 3 mm.
Note
£ Stathmostelma welwitschii can be readily distinguished from S£ £pedunculatum by the more branched growth form and the flowers which are yellow rather than red. Occasional specimens lack the tooth in the cavity of the corona lobe and can not therefore be assigned to the two varieties below.
[FTEA]

Sources

  • Angiosperm Extinction Risk Predictions v1

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

    • Flora Zambesiaca
    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • 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.
  • Kew Backbone Distributions

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. 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 2024. 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