Corresponding author: Erik J. M. Koenen (
Academic editor: Colin E. Hughes
The genus
Koenen EJM (2022)
The taxonomy and classification of the mimosoid legumes has seen significant changes over the last 35 years, including the disintegration of
In all this turmoil, a number of African species that have variously been placed in
While these African species are clearly similar to
Confusing pods of
Given the similarities and sister-group relationship with
Much confusion about relationships and generic classification in mimosoids (especially ingoids) has been caused by homoplasious fruit characters (
Fruit characters of
fruit shape | pod valve texture | septate between seeds | dehiscence | |
---|---|---|---|---|
straight, slightly curved, coiled and/or twisted | woody, papery to thinly ligneous or aerenchymous | yes | indehiscent or tardily breaking up into articles | |
contorted/ “ear-shaped” | woody | yes | indehiscent | |
straight to falcate or slightly curved | papery | yes | loment, seeds dispersed in 1-seeded articles | |
straight to falcate or slightly curved | papery or ligneous to woody | yes | loment, cryptoloment, follicular or indehiscent | |
straight | papery | no | dehiscent | |
straight or twisted | papery, thinly ligneous or woody | variable | dehiscent or indehiscent | |
straight, slightly curved or coiled/contorted | papery or woody | variable | dehiscent or tardily breaking up into articles | |
straight | papery, coriaceous or ligneous | variable | dehiscent, indehiscent, loment or cryptoloment | |
straight to slightly curved | thick and ligneous and/or fleshy | yes | indehiscent |
(i.e. the ingoid clade sensu
1 | Plants with prickles, stamens usually free or sometimes connate at base |
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– | Plants usually unarmed, rarely with spinescent shoots or stipular spines, stamens fused into a tube or at least connate at base |
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2 | Shrubs with elastically dehiscent pods |
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– | Trees or rarely shrubs with indehiscent, non-elastically dehiscent or lomentiform pods |
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3 | Trees with stipular spines, inflorescence spicate |
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– | Usually unarmed trees or with spinescent shoots, but never stipular spines, inflorescences capitate |
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4 | Fruit non-septate, with papery valves, usually dehiscent |
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– | Fruit septate, with thin fibrous or thick woody valves, indehiscent or lomentiform |
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5 | Peripheral flowers of capitulum on pedicels at least 1 mm long, leaves with (1–)2–3 pairs of pinnae, fruit lomentaceous with seeds dispersed as 1-seeded articles |
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– | Peripheral flowers on pedicels up to 0.5 mm long, leaves with (3–)5–30(–35) pairs of pinnae, fruit indehiscent or, if lomentiform, only tardily breaking up into articles |
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Three species in tropical Africa, from Senegal in the west to the Democratic Republic of Congo in the east and Zambia and Angola in the south. Typically occurring in rainforest and extending into the savannah zone in gallery forest.
The genus is named after “
Species of
1 | Leaves with fewer than 10 pairs of pinnae; fruits coiled or twisted, rarely only curved, flowers with 20–25 stamens |
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– | Leaves with more than 10 pairs of pinnae; fruit straight or somewhat curved, but not coiled nor twisted, flowers with 10–14 stamens |
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2 | Leaves of mature individuals (not those on coppice shoots) lacking nectaries between upper leaflet pairs, fruit a thick woody indehiscent pod, with uniform flat valves, not distinctly swollen over the seeds and rectangular in cross-section – West Africa (Upper Guinea) |
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– | Leaves usually with nectaries between the upper 1–3 leaflet pairs, fruit usually a flat sub-lomentiform indehiscent pod or sometimes a thicker woody pod, articulately swollen around the seeds, elliptic to circular in cross-section – Central and East Africa (Lower Guinea, Congolia and gallery forests in adjacent savannahs) |
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Ghana, Cape Coast, 7/41,
A specimen seen at Kew, of
The holotype of
The holotype of
1 | Leaflets typically asymmetrically hastate and weakly sigmoid, apex acute, usually > 3× as long as wide; fruits spirally-curved, coiled or twisted, 1-seeded articles (11–)13–17 mm wide and > (3–)4 mm thick when ripe – widespread in Lower and Upper Guinea |
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– | Leaflets weakly rhombic with oblique base, apex obtuse, ≤ 3× as long as wide; fruits spirally-coiled, 1-seeded articles 8–11 mm wide and 2–3 mm thick when ripe – Local in west Democratic Republic of Congo |
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Widespread across Upper and Lower Guinea and Congolia, from Guinea-Bissau in the west to the Democratic Republic of Congo in the east and Angola in the south (Fig.
Fresh-water swamp forest and along rivers in primary and secondary, evergreen or semi-deciduous rainforest.
Democratic Republic of Congo, Eala surroundings, Wangata-Watsiko, October 1943,
This subspecies was originally described as an infraspecific variety. I have considered treating it as a distinct species, but after studying material held at BR, I concluded it cannot be reliably separated from the typical subspecies across its entire range. The material stands out in its combination of slightly different leaf shape and smaller pods, but material outside the Busira river catchment in the Democratic Republic of Congo, as well as in other parts of Africa, is rather variable in leaf shape and pod size. Given that both these differences are consistently present in most of the material from that region, i.e. the variation is geographically structured within this variable and widespread species, subspecies is more appropriate than varietal rank and I treat it here as such.
Local to the Busira river catchment in the western Democratic Republic of Congo (Fig.
As the typical subspecies.
Liberia, Grand Bassa, 21 May 1897,
Upper Guinea, from Guinea-Bissau to Ghana (Fig.
Rainforest, gallery forest, wooded grassland, edges of mangrove swamp.
Democratic Republic of Congo, Kimuenza, 17 km S of Leopoldville, August 1910,
Lower Guinea and Congolia in Cameroon, Central African Republic, Gabon, Republic of the Congo, Democratic Republic of Congo, Angola (Fig.
Forest edges and gallery forest.
The second is
I thank Gwilym Lewis for acting as my SYNTHESYS+ host which made for an excellent visit to the legume collections at K. I also thank Jan Wieringa, William Hawthorne and Colin Hughes for useful comments that greatly improved the manuscript. My research was supported by the Swiss National Science Foundation (Early.Postdoc.Mobility fellowship P2ZHP3_199693 to EJMK) and by the SYNTHESYS+ project