Caesalpinioideae DC., Prodr. [A. P. de Candolle] 2: 473. 1825.

Bruneau, Anne, de Queiroz, Luciano Paganucci, Ringelberg, Jens J., Borges, Leonardo M., Bortoluzzi, Roseli Lopes da Costa, Brown, Gillian K., Cardoso, Domingos B. O. S., Clark, Ruth P., Conceicao, Adilva de Souza, Cota, Matheus Martins Teixeira, Demeulenaere, Else, de Stefano, Rodrigo Duno, Ebinger, John E., Ferm, Julia, Fonseca-Cortes, Andres, Gagnon, Edeline, Grether, Rosaura, Guerra, Ethiene, Haston, Elspeth, Herendeen, Patrick S., Hernandez, Hector M., Hopkins, Helen C. F., Huamantupa-Chuquimaco, Isau, Hughes, Colin E., Ickert-Bond, Stefanie M., Iganci, Joao, Koenen, Erik J. M., Lewis, Gwilym P., de Lima, Haroldo Cavalcante, de Lima, Alexandre Gibau, Luckow, Melissa, Marazzi, Brigitte, Maslin, Bruce R., Morales, Matias, Morim, Marli Pires, Murphy, Daniel J., O'Donnell, Shawn A., Oliveira, Filipe Gomes, Oliveira, Ana Carla da Silva, Rando, Juliana Gastaldello, Ribeiro, Petala Gomes, Ribeiro, Carolina Lima, Santos, Felipe da Silva, Seigler, David S., da Silva, Guilherme Sousa, Simon, Marcelo F., Soares, Marcos Vinicius Batista & Terra, Vanessa, 2024, Advances in Legume Systematics 14. Classification of Caesalpinioideae. Part 2: Higher-level classification, PhytoKeys 240, pp. 1-552 : 1

Subfamily Caesalpinioideae DC., Prodr. [A. P. de Candolle] 2: 473. 1825.

Caesalpiniaceae R. Br., in M. Flinders, Voy. Terra Austral. 2: 551. 1814. Type: Caesalpinia L.

Type.

Caesalpinia L.

Description.

Trees, shrubs, lianas, suffruticose or functionally herbaceous, occasionally aquatic, either unarmed or commonly armed with prickles, spines, or thorns; specialised extrafloral nectaries often present on the petiole and/or on the primary and secondary leaf rachides, usually between pinnae or leaflet pairs, more rarely stipular or bracteal. Stipules in lateral position and free or absent, usually entire, less frequently divided or spinescent. Leaves usually pulvinate, bipinnate, otherwise pinnate (sometimes both types on the same plant) and then mostly paripinnate, rarely imparipinnate, less often bifoliolate, modified into phyllodes or lacking, arrangement of the pinnae and leaflets mostly opposite, rarely alternate; stipels rare and not to be confused with the more commonly present paraphyllidia. Inflorescences globose or ellipsoid capitula, spicate, paniculate, racemose or in fascicles; bracteoles commonly small or absent. Flowers usually bisexual, rarely unisexual (species dioecious or monoecious), or bisexual flowers combined with unisexual and/or sterile flowers in heteromorphic inflorescences ( Mimoseae ), radially, less frequently bilaterally symmetrical, or asymmetrical; hypanthium lacking or cupular, rarely tubular; sepals (3) 5 (6-8), free or fused; petals (3) 5 (6-8), free or fused, the sepals or petals or both sometimes lacking, aestivation valvate ( Mimoseae ) or imbricate and then the adaxial petal innermost; stamens commonly diplostemonous or haplostemonous, sometimes reduced to 3 or 4 (in some Mimosa species), frequently polystemonous (to 100+ in some Mimoseae ), free or fused, sometimes heteromorphic, some or all sometimes modified or staminodial, anthers basifixed or dorsifixed, often with a stipitate or sessile apical gland, dehiscing via longitudinal slits or apical or basal poricidal slits or pores; pollen in tricolporate monads, or commonly in tetrads, bitetrads or polyads (most Mimoseae ); gynoecium uni- or rarely polycarpellate, 1-many-ovulate. Fruit typically dry and dehiscent, either a legume (dehiscent along both sutures) or a follicle (dehiscent along the adaxial suture only), or dry and segmented into one-seeded articles, either without a persistent margin (a lomentum) or with a persistent margins forming a replum like a frame (a craspedium), sometimes indehiscent and somewhat fleshy (an indehiscent legume), or dry and winged (a samara), when dehiscent with papery, leathery, or woody valves, dehiscence passive (inert valves), elastic, or explosive (the valves becoming curved, spirally coiled, or arched backwards), less frequently with entire valves, but with the endocarp segmented into one-seeded articles (a cryptolomentum). Seeds usually with an open (U-shaped) or closed (O-shaped) pleurogram on both faces or lacking a pleurogram, sometimes with a fleshy aril or sarcotesta, sometimes winged, in cross section terete (with a 1:1 ratio), compressed (with more or less 2:1 ratio) or flattened (with> 4:1 ratio; Gunn 1991); hilum usually apical, lens usually inconspicuous; embryo straight.

Chromosome number.

2 n mostly 24, 26, 28, but also reported 2 n = 14, 16, 20, 22, 36, 52, 54, 56, 72, 78, 104, 112.

Included taxa.

Caesalpinioideae in its emended circumscription contains eleven tribes, 163 genera and ca. 4680 species. Tribes: Caesalpinieae Rchb. (27 genera / ca. 223 species), Campsiandreae LPWG (2 / 5-22), Cassieae Bronn (7 / 695), Ceratonieae Rchb. (4 / 6), Dimorphandreae Benth. (4 / 35), Erythrophleeae LPWG (2 / 13), Gleditsieae Nakai (3 / 20), Mimoseae Bronn (100 / ca. 3510), Pterogyneae LPWG (1 / 1), Schizolobieae Nakai (8 / 42-43), Sclerolobieae Benth. & Hook. f. (5 / ca. 113) (Fig. 4 ).

Clade-based definition.

The most inclusive crown clade containing Arcoa gonavensis Urb. and Mimosa pudica L., but not Bobgunnia fistuloides (Harms) J.H. Kirkbr. & Wiersema, Duparquetia orchidacea Baill., or Poeppigia procera C. Presl.

Distribution and ecology.

Pantropical, common in both wet and dry regions, with a handful of species extending to the temperate zone, less frequently frost-tolerant ( Gleditsia J. Clayton, Gymnocladus Lam. and some species of Acacia Mill., Desmanthus Willd. and Senna Mill.). Caesalpinioideae species are infrequent above 2500 m in the tropics and are largely absent from mid- and high-elevation tropical montane forests. Generic diversity is highest in the Neotropics, and there are important centres of high species diversity in Mexico and Central America, central-east South America, Africa, Madagascar, parts of South East Asia and Australia (Fig. 3 , Table 1 ).

Notes.

This clade was referred to as the Mimosoideae - Caesalpinieae - Cassieae (MCC clade) ( Doyle 2011, 2012) or the Gleditsia - Chamaecrista - Mimosoideae (GCM clade) ( Marazzi et al. 2012). In LPWG (2017), Caesalpinioideae was chosen over Mimosoideae as the preferred name for the MCC clade, leaving open the option for naming the morphologically distinct mimosoid clade at the tribal level, as is done here (Fig. 5 ; see Mimoseae , page 201).

In the following treatments, the type species of different taxa are presented. Their homotypic (nomenclatural) synonyms are indicated by the identity symbol (≡) and heterotypic (taxonomic) synonyms by the equality symbol (=), as specified in the International Code of Nomenclature for algae, fungi, and plants ( Turland et al. 2018).

Figures

Figure 3. Map showing the global distribution of Caesalpinioideae genus richness. Numbers of Caesalpinioideae genera per one degree latitude / longitude grid cell.

Figure 4. Phylogeny of Caesalpinioideae showing the tribal classification presented here. The names and phylogenetic placements of all 63 non-Mimoseae Caesalpinioideae genera are shown and known generic non-monophyly is indicated with terminal names of non-monophyletic genus in bold. The most likely placements for four unsampled genera are indicated with dashed lines; see respective treatments for details. Tribe Mimoseae has been collapsed (see Fig. 5). Branch lengths are expressed in coalescent units, and terminal branch lengths have been assigned an arbitrary uniform length for visual clarity. Monophyletic genera are represented by single branches; see Suppl. material 2 for a phylogeny with all accessions. See Suppl. material 3 for gene tree support across the phylogeny. The phylogeny is a pruned version of the backbone phylogeny of Ringelberg et al. (2023), where full details of the data and phylogenomic analysis methods are presented.

Figure 5. Phylogeny of tribe Mimoseae showing the clade-based classification of the tribe with two named higher-level and 17 named lower-level clades. The names and phylogenetic placements of all 100 Mimoseae genera are shown, and known generic non-monophyly is indicated with terminal names of non-monophyletic genera in bold. The most likely placement of the unsampled genus Microlobius is indicated with a dashed line; see Stryphnodendron clade treatment (page 319) for details. Branch lengths are expressed in coalescent units, and terminal branch lengths have been assigned an arbitrary uniform length for visual clarity. Monophyletic genera are represented by single branches; see Suppl. material 2 for a phylogeny with all accessions. See Suppl. material 3 for gene tree support across the phylogeny. The phylogeny is a pruned version of the backbone phylogeny of Ringelberg et al. (2023) where full details of the data and phylogenomic analysis methods are presented.