Schizolobieae Nakai, Chosakuronbun Mokuroku [Ord. Fam. Tribe. Nov.]: 251. 1943.

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

publication ID	https://dx.doi.org/10.3897/phytokeys.240.101716
persistent identifier	https://treatment.plazi.org/id/B3B782F2-55A6-D5E2-23D0-24761A976714
treatment provided by	PhytoKeys by Pensoft
scientific name	Schizolobieae Nakai, Chosakuronbun Mokuroku [Ord. Fam. Tribe. Nov.]: 251. 1943.
status

Treatment

Tribe Schizolobieae Nakai, Chosakuronbun Mokuroku [Ord. Fam. Tribe. Nov.]: 251. 1943.

Figs 66 View Figure 66 , 67 View Figure 67 , 68 View Figure 68 , 69 View Figure 69 , 70 View Figure 70 , 71 View Figure 71 , 72 View Figure 72 , 73 View Figure 73 , 74 View Figure 74 , 75 View Figure 75 , 76 View Figure 76 , 77 View Figure 77

Type.

Schizolobium Vogel, Linnaea 11: 399. 1837.

Included genera

(8). Bussea Harms (7 species), Colvillea Bojer ex Hook. (1), Conzattia Rose (1), Delonix Raf. (12), Heteroflorum M. Sousa (1), Parkinsonia L. (12), Peltophorum (Vogel) Benth. (6-7), Schizolobium Vogel (2).

Description.

Trees or occasionally shrubs, (3) 5-40 m and up to 1.5 m stem diameter, typically branching low down with spreading, flat-topped crowns, some species of Delonix with swollen trunks; outer bark generally thin, pale silvery grey, or green, inner bark green; mainly unarmed, occasionally armed with axillary thorns, stipular spines and/or spinescent leaf rachides and spinescent side shoots; brachyblasts usually absent, rarely present. Stipules absent, minute, setiform, acicular and caducous, or lobed, pinnatifid or bipinnatifid, and persistent, or spinescent and persistent. Leaves bipinnate, variable in leaf formula, sometimes large, rarely paripinnate and much reduced. Inflorescences axillary racemes or terminal panicles, pedicels usually jointed. Flowers usually showy, almost always yellow, occasionally orange, whitish-pink or red, usually bisexual, but sometimes unisexual ( Heteroflorum , Conzattia , and Parkinsonia anacantha Brenan are at least partially dioecious); a distinct hypanthium always present, this generally short, discoid or shallowly campanulate, but larger and obliquely turbinate in Schizolobium ; sepals 5, subequal, either imbricate or valvate, free or partially fused, usually strongly reflexed; petals usually 5, occasionally 1, subequal or variable, longer or shorter clawed, usually crinkled, often with erose margins; stamens 10, usually spreading, rarely clustered around the ovary; pollen in oblate tricolporate monads with moderately to coarsely reticulate surface ornamentation. Fruits diverse, 1-many-seeded, usually flat, but sometimes terete or thickened, generally linear or linear-oblong or spathulate oblanceolate, the valves papery, coriaceous or woody, sutures sometimes thickened or with a narrow wing, indehiscent or dehiscent along both sutures, sometimes tardily so, usually inertly so, or rarely elastically from the apex. Seeds oblong-ellipsoid or ovate, discoid, lenticular and flattened to sub-spherical or globose, albuminous or ex-albuminous, integument hard.

Distribution.

Tribe Schizolobieae occupies a strikingly disjunct pantropical distribution spanning dry and wet tropical forests and savannas.

Clade-based definition.

The most inclusive crown clade containing Schizolobium parahyba (Vell.) S.F. Blake and Delonix decaryi (R. Vig.) Capuron, but not Caesalpinia brasiliensis L., Dimorphandra conjugata (Splitg.) Sandwith, or Mimosa sensitiva L. (Fig. 66 View Figure 66 ).

Notes.

Tribe Schizolobieae is here delimited to include eight genera and ca. 45 species. The monophyly and generic contents of this clade were first established using molecular data by Haston et al. (2003, 2005), and confirmed by Manzanilla and Bruneau (2012) and LPWG (2017), as well as in more recent phylogenomic analyses ( Ringelberg et al. 2022) which show robust support for this clade (Fig. 66 View Figure 66 ). Previously, these eight genera were spread across the informal Peltophorum and Caesalpinia groups of Polhill and Vidal (1981), while later Polhill (1994) expanded his concept of the informal Peltophorum group to include eight of these genera, but also eight other genera that are now placed in three other tribes, reflecting the poor understanding of generic relationships at that time across the then broadly circumscribed tribe Caesalpinieae .

Tribe Schizolobieae is equivalent to the Peltophorum group s.s. of Haston et al. (2005) and the informal core Peltophorum group of Lewis (2005b) with three Hoffmannseggia minor modifications. First, the addition of the genus Heteroflorum which, although mentioned by Lewis (2005b) and Haston et al. (2005), was only formally published that same year ( Sousa 2005). Second, new name combinations in Parkinsonia are now available for all species previously placed in the genus Cercidium Tul. ( Romão and Mansano 2021), which was shown to be nested within Parkinsonia ( Haston et al. 2003, 2005). Third, the genus Lemuropisum H. Perrier was shown to be nested within Delonix and sunk within that genus by Babineau and Bruneau (2017). In recent phylogenomic analyses ( Ringelberg et al. 2022), generic relationships within the tribe are also robustly supported (Fig. 66 View Figure 66 ).

Although varying markedly in stature, from shrubs and small trees to gigantic, buttressed trees up to 40 m tall in Schizolobium , all species of tribe Schizolobieae share a characteristic tree form and bark (Fig. 67 View Figure 67 ). Trees are typically forked low down with spreading umbrella-like, flat-topped crowns (Fig. 67 View Figure 67 ). The outer bark is generally smooth, thin and either pale silvery metallic grey, or, in most species of Parkinsonia and young trees of Schizolobium , green (Fig. 67 View Figure 67 ).

Leaf formula of the mainly bipinnate leaves (only Delonix edule has once-pinnate leaves) is highly variable among genera of Schizolobieae , ranging from highly reduced leaves with very short rachides and very reduced leaflets in some species of Parkinsonia , to what are some of the largest leaves of any genus in subfamily Caesalpinioideae , at 1-2 m long on young saplings of Schizolobium (Fig. 67C View Figure 67 ) and in Colvillea , which has leaves on non-flowering juvenile shoots with up to 2,000 leaflets.

The petals of flowers of all genera are showy, mainly bright yellow, but in some species of Delonix and Peltophorum orange, whitish-pink or red (Fig. 68 View Figure 68 ). Species of several genera are widely introduced and cultivated as ornamental trees in streets and gardens across the tropics. This includes the Flamboyant or Flame tree [ Delonix regia (Bojer ex Hook.) Raf.] (Fig. 67Q View Figure 67 ), one of the most widely cultivated ornamental trees in the tropics ( Lewis 2020a), several species of Peltophorum (Fig. 67D View Figure 67 ) and, in more arid regions, Parkinsonia , especially P. aculeata L. The showy flowers of several Schizolobieae have been the focus of botanical paintings (e.g., Colvillea racemosa Bojer, Bojer 1834; Delonix regia , Bojer 1829; Lewis 2020a). Species of several genera are naturalised and invasive following introductions, most notably Parkinsonia aculeata in northern Australia ( Hawkins et al. 2007).

While Schizolobieae can be found in all tropical vegetation types, the greatest diversity of genera and species occurs in the trans-continental succulent biome sensu Schrire et al. (2005a) which spans the Neotropics, Africa and Madagascar (Fig. 67F, I, L, O View Figure 67 ). Indeed, the robustly supported core clade comprising the genera Parkinsonia (amphi-Atlantic), Conzattia and Heteroflorum (endemic to Mexico), and Colvillea and Delonix (restricted to East Africa and Madagascar), represents one of the most striking examples of trans-continental phylogenetic succulent biome conservatism ( Ringelberg et al. 2020). The only exceptions in Schizolobieae to this overall predilection for the dry tropics are Schizolobium with two species in Neotropical wet forests and subsets of species of Bussea and Peltophorum in wet forests in Africa and Asia.