Rubiaceae

Tricalysia A.Rich. ex DC.

First published in Prodr. 4: 445 (1830)
This genus is accepted
The native range of this genus is Tropical & S. Africa, W. Indian Ocean.

Descriptions

Rubiaceae, D.M.Bridson & B.Verdcourt. Flora Zambesiaca 5:3. 2003

Morphology General Habit
Mostly shrubs, less often small trees or large dominant trees (a few species, not in the Flora); rarely rhizomatous undershrubs.
Morphology Leaves
Leaves evergreen or deciduous, sometimes dimorphic (blades at start of new season’s growth, smaller and broader than main leaves, TAB. 92/A), subsessile to petiolate, often with domatia, never with bacterial nodules; stipules sheathing, each limb awned.
Morphology Reproductive morphology Inflorescences
Inflorescences axillary and sessile, subsessile or infrequently shortly pedunculate, 1–several-flowered, usually compact; bract and bracteoles similar, opposite pairs fused to form cup-like structures (cupules), with leaf-derived and stipule-derived lobes (the latter occasionally subfoliaceous) apparent (TAB. 92/B2), or more often with (0 or 2)4 shorter awns and somewhat resembling the calyx limb (TAB. 92/B3–B5), arranged in a series, subtending the usually condensed inflorescence branches with the uppermost cupule subtending and frequently surrounding the calyx tube (Tab. 92/B6) or, sometimes chaffy in texture, entire in young bud then irregularly splitting (TAB. 92/B1), less often (not in Flora Zambesiaca area), alternate and not fused; bractlets (bracteoles fide Robbrecht) free in pedicellate species, either opposite or alternate (TAB. 92/B1).
Morphology Reproductive morphology Flowers
Flowers (4)5–9(12)-merous, mostly sweet-scented, sessile or less often pedicellate, hermaphrodite (with the exception of a unisexual group of Madagascan species), occasionally dimorphic (sect. Ephedranthera, TAB. 92/D1&D2).
Morphology Reproductive morphology Flowers Calyx
Calyx very variable, either with a short limb-tube and distinct lobes (subgen. Empogona, TAB. 92/C1–C3) or with well developed, truncate or dentate limb-tube (subgen. Tricalysia, TAB. 92/C4–C9).
Morphology Reproductive morphology Flowers Corolla
Corolla mostly white, sometimes greenish, cream-coloured or rose-coloured, salver-shaped; lobes spreading or reflexed, contorted to the left.
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens attached to the throat, mostly with distinct filaments; anthers medifixed, exserted, rarely (sect. Ephedranthera) sessile and half-included to almost completely included, with or without an inconspicuous or markedly conspicuous apical appendage formed by an extension of the connective.
Morphology Reproductive morphology Flowers Disc
Disk annular.
Morphology Reproductive morphology Flowers Gynoecium Pistil
Ovary 2-locular, with 1–many ovules embedded in a placenta attached to the septum; style 2-lobed, exserted, lying between the anthers or just overtopping them, but deeply included in the short-styled form of sect. Ephedranthera (TAB. 92/D2).
Morphology Reproductive morphology Fruits
Fruits ± drupe-like, mostly less than 1 cm in diameter, rarely somewhat larger and with a ± dry, sclerified indehiscent wall (not in Flora Zambesiaca area), mostly red, rarely orange, or in subgen. Empogona first white then turning blackish; calyx limb mostly persistent; endocarp papery.
Morphology Reproductive morphology Seeds
Seeds 1–many per locule (rarely only 1 per fruit by abortion of the second chamber); seed coat chestnut-brown, colliculate, striate or smooth; hilum long, linear, often curved or with a small excavation; endosperm horny in texture; embryo straight, attaining at most half the height of the seed; cotyledons ± equalling the basally oriented radicle.
[FZ]

Rubiaceae, B. Verdcourt. Flora of Tropical East Africa. 1976

Morphology General Habit
Mostly shrubs, less often small trees or (only a few species, not in the Flora area) large dominant trees; rarely (± 6 species) rhizomatous undershrubs
Morphology Leaves
Leaves petiolate, often with domatia, never with bacterial nodules; stipules sheathing, crowned by two awns
Morphology Reproductive morphology Inflorescences
Inflorescences axillary and opposite, sessile to subsessile, rarely 1-, mostly many-flowered and strongly contracted
Morphology Reproductive morphology Flowers
Flowers (4–)5–9(–12)-merous, mostly sweetly scented, sessile or rarely pedicellate, hermaphrodite (with the exception of a group of Madagascan species which is unisexual), occasionally dimorphic (sect. Ephedranthera)
Morphology Reproductive morphology Inflorescences Bracts
Bracts (primary and secondary etc.) and bracteoles similar and arranged in a series or less often dissimilar, paired, fused, cupular and somewhat resembling the calyx-limb or less often dissimilar to calyx-limb, dentate, awned or occasionally with leafy appendages, subtending the usually condensed inflorescence branches and with 1 (–3 in simple inflorescences) cup subtending and frequently surrounding each calyx-tube; in some pedicellate species bracteoles free, either opposite or alternate
Morphology Reproductive morphology Flowers Calyx
Calyx very variable, either with short limb-tube and distinct lobes (subgen. Empogona) or with well-developed, truncate or dentate limb-tube
Morphology Reproductive morphology Flowers Corolla
Corolla mostly white, sometimes greenish, cream or rose, salver-shaped; lobes spreading or reflexed, contorted to the left
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens attached to the throat, mostly with distinct filaments; anthers medifixed, exserted, rarely (sect. Ephedranthera) sessile and half-included to almost completely included, with or without an inconspicuous or markedly conspicuous apical appendage formed by an extension of the connective
Morphology Reproductive morphology Flowers Disc
Disc annular
Morphology Reproductive morphology Flowers Gynoecium Pistil
Ovary 2-locular, with 1–many ovules embedded in a placenta attached to the septum; style 2-lobed, exserted, lying between the anthers or just overtopping them, but deeply included in the short-styled form of sect. Ephedranthera
Morphology Reproductive morphology Fruits
Fruits ± drupaceous, mostly less than 1 cm. in diameter, rarely (sect. Probletostemon and T. allocalyx) somewhat larger and with ± dry, sclerified indehiscent wall, mostly red, rarely orange, in subgen. Empogona first white then turning blackish; calyx mostly persistent; endocarp papery
Morphology Reproductive morphology Seeds
Seeds 1–many per locule (rarely only 1 per fruit by abortion of the second chamber); seed-coat chestnut-brown, colliculate, striate or smooth; hilum long, linear, often curved; endosperm horny; embryo straight, attaining at most 1/2 the height of the seed; cotyledons ± equalling the basally oriented radicle.
[FTEA]

M. Thulin. Flora of Somalia, Vol. 1–4 [updated 2008] https://plants.jstor.org/collection/FLOS

Distribution
Genus of more than 100 species in Africa and Madagascar.
Morphology General Habit
Shrubs or small trees
Morphology Leaves
Leaves opposite; stipules sheathing, aristate
Morphology Reproductive morphology Flowers
Flowers mostly 5–9-merous, isostylous, in axillary clusters or solitary; bracts often cup-shaped
Morphology Reproductive morphology Flowers Calyx
Calyx with short to prominent limb-tube
Morphology Reproductive morphology Flowers Corolla
Corolla-tube cylindrical to funnel-shaped; lobes contorted, overlapping to the left in bud
Morphology Reproductive morphology Flowers Gynoecium Ovary
Ovary 2-celled with 1–many ovules per cell embedded in a placenta attached to the septum; style 2-lobed
Morphology Reproductive morphology Fruits
Fruit indehiscent, ± fleshy and drupaceous
Morphology Reproductive morphology Seeds
Seeds 1–many, brown.
[FSOM]

Sources

  • Flora Zambesiaca

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

  • Flora of Somalia

    • Flora of Somalia
    • 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 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