Orchidaceae
Disa

Disa robusta N.E.Br.

First published in D.Oliver & auct. suc. (eds.), Fl. Trop. Afr. 7: 282 (1898)
This species is accepted
The native range of this species is E. Central Tropical Africa. It is a tuberous geophyte and grows primarily in the seasonally dry tropical biome.

Descriptions

Orchidaceae, I. la Croix and P.J. Cribb. Flora Zambesiaca 11:1. 1995

Morphology General Habit
Terrestrial herb with separate fertile and sterile shoots; perennating by testicular tubers.
Morphology General Shoots
Sterile shoots to 10 cm tall, 2–4-leaved; leaves semi-erect, conduplicate, up to 30 cm long, lanceolate to narrowly elliptic, acute. Fertile shoots 60–80 cm tall; cauline leaves imbricate, almost completely sheathing, grading into the floral bracts, 6–9 cm long, obtuse to acute.
Sterile
Sterile shoots to 10 cm tall, 2–4-leaved; leaves semi-erect, conduplicate, up to 30 cm long, lanceolate to narrowly elliptic, acute.
Fertile
Fertile shoots 60–80 cm tall; cauline leaves imbricate, almost completely sheathing, grading into the floral bracts, 6–9 cm long, obtuse to acute.
Morphology Reproductive morphology Inflorescences
Inflorescence sub-dense, 7–15(30) cm long, 10–20(40)-flowered.
Morphology Reproductive morphology Inflorescences Bracts
Floral bracts ovate to narrowly ovate, acute to acuminate, reaching to the middle of the flowers.
Morphology Reproductive morphology Flowers
Flowers facing down at an angle of 45°, orange-red.
Morphology Reproductive morphology Flowers Spur
Spur horizontal from a broadly conical base, 25–35 mm long, constricted in the middle, the apex sub-clavate, usually upcurved, ascending due to the angle of the flowers.
Morphology Reproductive morphology Flowers Calyx
Lateral sepals 12–18 mm long, broadly ovate to broadly oblong, subacute. Dorsal sepal galeate; galea rounded, 10–16 mm long, 9–12 mm wide and 7–8 mm deep, broadly ovate.
Morphology Reproductive morphology Flowers Corolla
Petals 11–18 mm long, oblanceolate, acute, erect, falcate.
Morphology Reproductive morphology Flowers Labellum
Lip 7–12 mm long, narrowly oblong, acute.
Morphology Reproductive morphology Flowers Rostellum
Rostellum lateral lobe parallel, 2–3 mm tall.
Morphology Reproductive morphology Flowers Androecium Stamens Anthers
Anther 4–5 mm long.
Morphology Reproductive morphology Flowers Gynoecium Stigma
Stigma stipitate.
Morphology Reproductive morphology Flowers Gynoecium Ovary
Ovary 2–3 cm long.
[FZ]

Orchidaceae, V. S. Summerhayes. Flora of Tropical East Africa. 1968

Morphology General Habit
A terrestrial herb 2–8.5 dm. high, glabrous except for the roots.
Vegetative Multiplication Tubers
Tubers ovoid, ellipsoid or nearly spherical, sometimes forked, 1.5–5 cm. long, 1.5–3.5 cm. in diameter, shortly tomentose to nearly glabrous.
Morphology Roots
Roots slender, flexuous, softly hairy.
Morphology Stem
Flowering stem erect, robust or rather robust, often 1 cm. in diameter near the base, terete, leafy throughout its length; leaves 9–13, the lowermost sheath-like, spotted with red or purple, the remainder erect and adpressed to the stem, lanceolate, acute, the largest 5–10 cm. long, 1.5–3 cm. broad, decreasing in size up the stem. Sterile stem 5–14 cm. long, covered by 3 or 4 overlapping red-spotted or red-barred sheaths, with 1–3 leaves at the apex; leaves elliptical-lanceolate or elliptical-oblanceolate, acute, 8–29 cm. long and 2–6 cm. broad.
Morphology Reproductive morphology Inflorescences
Inflorescence 8–27 cm. long, when flowers are expanded 6–7 cm. in diameter, rather loosely to densely 3- to many-flowered.
Morphology Reproductive morphology Inflorescences Bracts
Bracts leafy, lanceolate, acute, 1.5–5.5 cm. long, usually shorter than the flowers.
Morphology Reproductive morphology Flowers
Flowers suberect or ± spreading, orange to vermilion; pedicel with ovary straight, 1.5–2.8 cm. long.
Morphology Reproductive morphology Flowers Calyx
Dorsal sepal elongate-conical to narrowly conical, the spur often not clearly separable from the remainder, from base to true apex 1–2 cm. long, the mouth when spread out 1.5–3.5 cm. broad, the spur erect, broad at its base, slightly thickened in the apical part, often bent at the narrow centre, total length from base of dorsal sepal to apex 2–5 cm.; laterals spreading or defiexed, elliptical or ovate-elliptical, obtuse or rounded, 8–17 mm. long, 6–11 (–17) mm. broad.
Morphology Reproductive morphology Flowers Corolla
Petals erect, inside the dorsal sepal, falcate- or curved-lanceolate, acute, widened and rounded at the base, adnate to the column in the basal part, 9–17 mm. long, 2–5.5 mm. broad.
Morphology Reproductive morphology Flowers Labellum
Lip pendulous or curved forwards, linear, 7–12 mm. long, 1–2.5 mm. broad.
Morphology Reproductive morphology Flowers Column
Column erect, ± 3 mm. high; anther terminal, horizontal, 5 mm. long, canals very short, 0.5 mm. long; stigma vertical, transversely elliptical, 4.5 mm. broad.
Habitat
Upland grassland often rich in herbs, or open spaces in Brachystegia woodland; 900–2700 m.
Distribution
T4 T7 T8
[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 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