Stathmostelma gigantiflorum K.Schum.

First published in Bot. Jahrb. Syst. 17: 129 (1893)
This species is accepted
The native range of this species is Kenya to E. Zambia. It is a climbing tuberous geophyte and grows primarily in the seasonally dry tropical biome.

Descriptions

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
Bot. Jahrb. Syst. 17:t.6, figs.A–C (1893), lectotype designated by Goyder in Kew Bull. 53: 599 (1998).
Morphology General Habit
Perennial herb with a single branched annual stem arising from a stout napiform or globose tuber; stem 0.3–1 m long, branched from near the ground, erect or ascending, minutely pubescent with short white hairs
Morphology Leaves
Leaves mostly subsessile, occasionally with petiole to 10 mm long; lamina 10–25 × 0.2–1(2) cm, linear or occasionally lanceolate, acute, base cuneate, indumentum mostly restricted to margins and midvein
Morphology Reproductive morphology Inflorescences
Inflorescences terminal and extra-axillary with 3–6 flowers in an erect umbel; peduncles 2–17 cm long, the lower inflorescences generally with longer peduncles than the upper ones, erect, minutely pubescent; bracts filiform, pubescent; pedicels 2–5 cm long, minutely pubescent
Morphology Reproductive morphology Flowers Calyx
Sepals 6–12(14) × 2–3(9) mm, triangular to broadly ovate, acute, subglabrous to densely pubescent
Morphology Reproductive morphology Flowers Corolla
Corolla rotate to slightly reflexed, subglabrous or pubescent on outer surface, minutely papillose within, white or green outside, white, green or pink and occasionally speckled purple within; lobes (15)20–30 × 7–15 mm, ovate to elliptic, acute, somewhat replicate
Morphology Reproductive morphology Flowers Gynostegium
Gynostegium with stipe c.3 mm long
Morphology Reproductive morphology Flowers Corona
Corona lobes white or green, frequently speckled with purple towards upper margin, 8–15 × 4–7 mm, mostly overtopping column by at least half their length, erect, concave-cucullate for most of their length, weakly pouched either side of the mid line towards the base, apex rounded to attenuate distally, the inner apical margins produced into a pair of upward- or inward-pointing acute teeth, inner margins of lobe papillose, cavity without a median tooth
Morphology Reproductive morphology Flowers Androecium Stamens Anthers
Anther wings 4–6 mm long, curved, the basal tails free from the column; anther appendages c.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, 10–16 × 0.5–0.8 cm, narrowly fusiform, with a basal stipe, not inflated, smooth, minutely but densely pubescent
Morphology Reproductive morphology Seeds
Seeds c.3 × 2 mm, verrucose.
Distribution
Zambia, Malawi. Also reported from Kenya and Tanzania.
Ecology
Seasonally waterlogged grassland on black clay soils; 500–1800 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 a single branched annual stem arising from a stout napiform or globose tuber.
Morphology Stem
Stem erect or ascending, 0.3–1 m long, branched from near the ground, minutely pubescent with short white hairs
Morphology Leaves
Leaves mostly subsessile, occasionally with petiole to 10 mm long; lamina linear or occasionally lanceolate, 10–25 × 0.2–1(–2) cm, acute, base cuneate, indumentum mostly restricted to margins and midvein.
Morphology Reproductive morphology Inflorescences
Inflorescences terminal and extra-axillary with 3–6 flowers in an erect umbel.
Morphology Reproductive morphology Inflorescences Peduncles
Peduncles erect, 2–17 cm long, the lower inflorescences generally with longer peduncles than the upper ones, minutely pubescent.
Morphology Reproductive morphology Inflorescences Bracts
Bracts filiform, pubescent.
Morphology Reproductive morphology Flowers Calyx
Sepals triangular to broadly ovate, 6–12(–14) × 2–3(–9) mm, acute, subglabrous to densely pubescent
Morphology Reproductive morphology Flowers Corolla
Corolla rotate to slightly reflexed, subglabrous or pubescent on outer surface, minutely papillose within, white or green outside, white, green or pink and occasionally speckled purple within; lobes ovate to elliptic, (15–)20–30 × 7–15 mm, acute, somewhat replicate
Morphology Reproductive morphology Flowers Gynostegium
Gynostegium with stipe ± 3 mm long
Morphology Reproductive morphology Flowers Corona
Corona lobes erect, white or green, frequently speckled with purple towards upper margin, 8–15 × 4–7 mm, mostly overtopping column by at least half their length, concave-cucullate for most of their length, weakly pouched either side of the midline towards the base, apex rounded to attenuate distally, the inner apical margins produced into a pair of upward- or inward-pointing acute teeth, inner margins of lobe papillose, cavity without a median tooth
Morphology Reproductive morphology Flowers Androecium Stamens Anthers
Anther wings 4–6 mm long, curved, the basal tails free from the column; anther appendages ± 1.5 mm long, semicircular and inflexed over apex of stylar head; corpusculum black, obovoid to subcylindrical, ± 0.7 × 0.3 mm; translator arms with a membranous, obovate, convex and somewhat contorted proximal part ± 3.5 × 1.5 mm, and a filiform distal part ± 1 mm long broadening abruptly into a clasping overlap with the pollinium.
Morphology Reproductive morphology Flowers Pollinia
Pollinia oblong, ± 1.5 × 0.5 mm, flattened
Morphology Reproductive morphology Flowers Gynoecium Style
Stylar head flat
Morphology Reproductive morphology Flowers Pedicel
Fruiting pedicel not contorted. Pedicels 2–5 cm long, minutely pubescent
Morphology Reproductive morphology Fruits
Follicle erect, narrowly fusiform, 10–16 × 0.5–0.8 cm, with a basal stipe, not inflated, smooth, minutely but densely pubescent
Morphology Reproductive morphology Seeds
Seeds ± 3 × 2 mm, verrucose.
Ecology
Seasonally waterlogged grassland on black clay soils; 500–1800 m
Note
The broadly ovate sepals of S. gigantiflorum sensu Bullock (1953a) contrast with the lanceolate sepals of other collections but as the other differences listed by Bullock can be observed elsewhere in the complex I have chosen to interpret the two collections as extreme variants within a variable species. Collections from Kenya and southern Tanzania have distinctive facies recognised by Bullock (1953a, 1953b) when he described S. praetermissum and S. nomadacridum. However, the characters which combine to give these appearances (principally the form of the apex and teeth of the corona lobes) break down in the intervening territory. I have reluctantly come to the conclusion that, as it is only possible to divide the variation on completely arbitrary grounds, the species must be redefined in the broad sense of N.E. Brown (1902) with no infraspecific taxa recognised. S. bicolor ( A. muhindensis) appears, from the limited material available (a single flower from the type), to be a poorly developed specimen of S. gigantiflorum and I have therefore included it in the synonymy of this species. Bidgood et al. 2295 from Chunya district in southern Tanzania probably also belongs here but has exceptionally broad leaves and smaller corona lobes than in other material.
Distribution
Flora districts: K4 T1 T2 T4 T5 T7 Range: E Zambia and central Malawi
[FTEA]

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]

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.
    • 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 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