Caesalpinia Plum. ex L.

Legumes of the World. Edited by G. Lewis, B. Schrire, B. MacKinder & M. Lock. Royal Botanic Gardens, Kew. (2005)

Habit

Trees and shrubs

Ecology

Seasonally dry tropical woodland, wooded grassland, coastal thicket, bushland and thorn scrub, dry plains and riparian woodland, many species on limestone or sandstone

Distribution

Caribbean (10 in Hispaniola, Cuba and the Bahamas), Mexico (2-3 spp., 1 extending to C America), 1 in Colombia, Ecuador and Peru, 1 in Paraguay and Argentina, 1 endemic to Madagascar, 10 in Africa (1 endemic in Congo [Kinshasa], 5 restricted to southern Africa, 4 restricted to the E and NE, with 1 extending into Oman, S Yemen and Arabia)

Note

Few species of Caesalpinia sens. strict. have been included in molecular analyses to date, but Simpson et al. (2003) found strong support for a grouping of C. rosei Urb. from the Dominican Republic, C. sessiliflora S.Watson from Mexico and C. madagascariensis (R.Vig.) Senesse from Madagascar, as well as strong support for C. cassioides Willd. from NW South America being sister to C. pulcherrima (L.) Sw. from Mexico and C America. An additional 12-15, predominantly Asian, species which do not belong to Caesalpinia sens. strict. are provisionally placed here (see introductory text to tribe). Their affinity is rather to a cluster of associated taxa which require further study before they can be placed into genera. These taxa include Caesalpinia sect. Sappania Benth., sect. Nugaria (DC.) Benth., sect. Cinclidocarpus (Zoll.) Benth., and the previously recognised genera Biancaea Tod., Campecia Adans. and Ticanto Adans.

Polhill & Vidal (1981) divided the Caesalpinieae into 8 informal generic groups: the Gleditsia group (2 genera), the Acrocarpus group (monogeneric), the Sclerolobium group (3 genera), the Peltophorum group (13 genera), the Caesalpinia group (16 genera), the Poeppigia and Pterogyne groups (both monogeneric) and the Dimorphandra group (10 genera). They commented that the tribe is “a remarkable mixture of relics and complexes of relatively recent speciation, providing many pitfalls for formal systematics and biogeographical interpretations”. Polhill (1994) added a ninth informal group, the monogeneric Orphanodendron group, and placed Cordeauxia as a synonym of Stuhlmannia (both genera recognised in the present treatment) so that the total of 47 genera in the tribe remained unchanged. Within the tribe, Parkinsonia (including Cercidium), Conzattia and Lemuropisum were moved from the Caesalpinia group to the Peltophorum group (Polhill, 1994) in agreement with the subsequently published works of Lewis & Schrire (1995) and Du Puy et al. (1995b).

Since 1994 several studies have cast new light on intergeneric relationships within the Caesalpinieae, necessitating the restructuring of some of the nine informal generic groups presented by Polhill (1994). As pointed out in the introduction to tribe Cassieae, the genus Ceratonia has been removed from that tribe to the Caesalpinieae, and Poeppigia has been removed from the Caesalpinieae to the Cassieae (for further detail see discussion under each genus). In the rbcL phylogeny of Doyle et al. (1997) the Caesalpinieae, as traditionally circumscribed, was shown to be paraphyletic with members scattered throughout a clade which also included genera of the Cassieae and one mimosoid genus. The molecular analysis of Kajita et al. (2001) also found the Caesalpinieae to be non-monophyletic. In the molecular analysis of Bruneau et al. (2001) some of the informal generic groups of Polhill (1994) were supported as monophyletic but the tribe as a whole was clearly demonstrated to be paraphyletic. With regard to intergeneric relationships, Pterogyne resolved as sister to a Caesalpinia group clade; Batesia and Vouacapoua fell outside a core- Peltophorum group, and the Dimorphandra group was clearly shown to be a diverse assemblage of genera, many of which share certain characteristics with the Mimosoideae, specifically with members of tribe Mimoseae (Bruneau et al., 2001). Erythrophleum was sister to a clade that comprised the majority of the Mimosoideae sampled, and Pachyelasma was sister to the two mimosoid genera Pentaclethra and Calpocalyx. Herendeen et al. (2003a) in a combined molecular-morphological analysis which expanded on the study of Bruneau et al. (2001), presented an ‘Umtiza clade’ containing Gymnocladus and Gleditsia (the two members of Polhill and Vidal’s Gleditsia Group), Umtiza (traditionally included in tribe Detarieae), Tetrapterocarpon (from the Dimorphandra Group), Acrocarpus (the sole genus of the Acrocarpus Group), and Ceratonia (from subtribe Ceratoniinae in tribe Cassieae). This new generic grouping raises some fascinating phytogeographical questions (see Schrire et al., pages 21–54, this volume). Pterogyne resolved as sister to a Chamaecrista-Senna clade (of tribe Cassieae) a relationship worthy of further study; Batesia and Vouacapoua again fell outside the core-Peltophorum group; Dimorphandra grouped with Mora as sister to all Mimosoideae, and Pachyelasma grouped with Erythrophleum as sister to the Dimorphandra-Mimosoideae clade. In the phylogenetic investigation of Haston et al. (2003), the Peltophorum group of Polhill (1994) was non-monophyletic but there was support for a core-Peltophorum group comprising Peltophorum, Parkinsonia, Schizolobium, Conzattia, Delonix, Lemuropisum, Colvillea and Bussea. Pterogyne resolved as sister to a clade containing Haematoxylum and Cordeauxia (both of the Caesalpinia group), thus supporting the earlier findings of Bruneau et al. (2001) rather than those of Herendeen et al. (2003a). Haston et al. (submitted) have further refined the relationships of the non core-Peltophorum group genera. They place Arapatiella and Jacqueshuberia with Tachigali in a newly defined Tachigali group and find strong molecular support for associating Batesia with Recordoxylon and Melanoxylon in a new Batesia group. Moldenhawera is placed in its own monogeneric group sister to a Tachigali group–core-Peltophorum group–Dimorphandra group–Mimosoideae clade. In an analysis testing the monophyly of the Umtiza clade (Herendeen et al., 2003b), Arcoa (traditionally of the Dimorphandra group) from the Dominican Republic was added to the group of genera in that clade.

Without doubt, the genus with the greatest taxonomic and nomenclatural complexity within the Caesalpinieae is the type genus Caesalpinia, which in its broadest sense comprises c. 140 spp. and contains 25 generic names in synonymy. Of these 140 species, 12–15 predominantly Asian taxa have still to be included in molecular studies and cannot yet be assigned to any generic segregate recognised in this treatment (see notes under Caesalpinia L.). Studies by Lewis & Schrire (1995), Simpson & Miao (1997), Lewis (1998), Simpson (1998, 1999), Simpson & Lewis (2003) and Simpson et al. (2003), have clearly demonstrated that Caesalpinia, as traditionally circumscribed, is polyphyletic. In this treatment Hoffmannseggia is recognised as distinct following Simpson & Miao (1997), Simpson (1999) and Ulibarri (1979, 1996); Pomaria is also segregated from Caesalpinia sens. lat. following Simpson (1998) and Simpson & Lewis (2003). The genera Coulteria, Erythrostemon, Guilandina, Libidibia, Mezoneuron, Poincianella and Tara are also reinstated following the findings of Lewis & Schrire (1995), Lewis (1998), Simpson et al. (2003), Lewis & Bruneau (unpublished), Lewis & Lavin (unpublished) and Sotoyo (unpublished). Caesalpinia sens. strict. is, in consequence, reduced to a genus of 25 species.

The Caesalpinieae as presented here contains 56 genera and (423)–436–(448) species (Fig. 23). Thirty two of the genera contain 3 or fewer species each, with 23 monospecific (a second species of Orphanodendron has apparently been discovered in Colombia, but is, as yet, undescribed [Cogollo Pacheco, pers. comm., 2002]). A new genus, tentatively named as Heteroflorum by Sousa & Delgado (1993), but not yet formally published, is a monospecific Mexican endemic closely related to Conzattia. It is not dealt with here. The informal generic groups of tribe Caesalpinieae presented by Polhill & Vidal (1981) and Polhill (1994) are retained in part in Fig. 23 which accompanies this treatment, but there are some noteworthy exceptions. The Gleditsia and Acrocarpus groups are both subsumed into the ‘Umtiza clade’; Diptychandra is rejected from the Sclerolobium group which now becomes the Tachigali group and includes Arapatiella and Jacqueshuberia; Poeppigia is moved to the Cassieae; several genera are removed from the Peltophorum group leaving a core of nine related genera (if Heteroflorum is included); Batesia, together with Recordoxylon and Melanoxylon constitutes a new Batesia group based on the work of Haston et al. (submitted). Moldenhawera is placed in its own group as its generic relationships are currently unclear (Haston et al., submitted). The Caesalpinia group increases in size from 12 to 21 genera. Five genera are currently too poorly known for them to be placed with confidence: Campsiandra, Chidlowia, Diptychandra, Orphanodendron and Vouacapoua.

Leguminosae, R.K. Brummitt, A.C. Chikuni, J.M. Lock & R.M. Polhill. Flora Zambesiaca 3:2. 2007

Morphology Leaves

Leaves bipinnate with paired pinnae; leaflets opposite, glandular or eglandular; without specialised glands on petiole and rachis, though sometimes with a general glandular indumentum; stipules minute to conspicuous and leafy.

Morphology Reproductive morphology Flowers

Flowers in terminal or lateral racemes or panicles, these rarely much reduced to single or few flowers; bracts usually caducous.

Morphology Reproductive morphology Flowers Hypanthium

Hypanthium shallow, ± obconic.

Morphology Reproductive morphology Flowers Calyx

Sepals 5, imbricate to sometimes almost valvate, the lowermost curving up to overlap the other 4.

Morphology Reproductive morphology Flowers Corolla

Petals 5, subequal except for the uppermost one which is usually modified in shape and size.

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 10, alternately longer and shorter; filaments pubescent to villous and often glandular in the lower part; anthers dorsifixed, dehiscing by longitudinal slits.

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary ± sessile or shortly stipitate, glabrous or with various indumentum; stigma truncate or oblique, ciliolate or glabrous.

Morphology Reproductive morphology Fruits

Pods very variable, usually compressed, not winged, dehiscent or not, sometimes spiny; seeds variable, endosperm present or absent.

Morphology General Habit

Shrubs, erect or usually scrambling or climbing, or sometimes trees, usually armed with spines or prickles but sometimes unarmed.

Leguminosae, J. B. Gillett, R. M. Polhill & B. Verdcourt. Flora of Tropical East Africa. 1971

Morphology General Habit

Shrubs, erect or more often scrambling or climbing, or trees, armed with spines or prickles or sometimes unarmed

Morphology Leaves

Leaves bipinnate, very rarely (and not in East Africa) reduced to scales (“switch-plant” habit); stipules various, minute to conspicuously leafy; specialized glands restricted to petiole and rhachis absent, although a general glandular indumentum may be sometimes present; leaflets opposite, rarely alternate, glandular or sometimes eglandular

Morphology Reproductive morphology Inflorescences

Inflorescences of terminal, sometimes falsely lateral, or terminal and axillary racemes or panicles; rarely racemes much reduced, the flowers thus single or very few together; bracts usually quickly falling

Morphology Reproductive morphology Flowers

Flowers hermaphrodite, or ♂ ⚥ in C. bonduc and C. volkensii among native species

Morphology Reproductive morphology Flowers Calyx

Sepals 5, imbricate, sometimes very narrowly so, or almost valvate; the lower sepal often cucullate at apex and clasping the others

Morphology Reproductive morphology Flowers Corolla

Petals 5, subequal except for the usually somewhat modified upper one, which usually has a rather smaller lamina and more pronounced claw

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 10, fertile, rarely and casually with 1 ± abortive; filaments alternately longer and shorter, all pubescent or villous and often glandular below; anthers dorsifixed, dehiscing by longitudinal slits

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary free, subsessile or shortly stipitate, usually with 2 to ± 10 ovules, glabrous, pubescent or glandular; style glabrous, or clothed below like the ovary; stigma truncate or oblique, ciliolate or glabrous

Morphology Reproductive morphology Fruits

Pods very variable, usually flat or ± compressed, very rarely cylindrical, not winged, indehiscent or dehiscent and 2-valved, hard and woody or thick and pulpy

Morphology Reproductive morphology Seeds

Seeds transverse or nearly so, hard; funicle short; endosperm present or absent.

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

Morphology General Habit

Shrubs, often climbing, or trees, often with spines or prickles

Morphology Leaves

Leaves bipinnate, without specialised glands (sometimes with glandular hairs); leaflets usually opposite, often glandular

Morphology Reproductive morphology Flowers

Flowers in racemes or panicles

Morphology Reproductive morphology Flowers Calyx

Sepals 5, imbricate, the lower one often largest and hooded

Morphology Reproductive morphology Flowers Corolla

Petals 5, subequal except for the generally smaller upper one

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 10; filaments alternately longer and shorter, hairy and often glandular below

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary subsessile to shortly stipitate; ovules c. 2–10

Morphology Reproductive morphology Fruits

Pods various, usually flattened, not winged, dehiscent or not; valves coriaceous, woody or pulpy, sometimes spiny

Morphology Reproductive morphology Seeds

Seeds transverse or nearly so, hard.

Distribution

A tropical genus of c. 150 species, most numerous in the New World.