Piptadenia Benth., J. Bot. (Hooker) 4: 334. 1841.

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

Piptadenia Benth., J. Bot. (Hooker) 4: 334. 1841.

Figs 182 , 183

Lectotype.

Piptadenia latifolia Benth. [= Piptadenia adiantoides (Spreng.) J.F. Macbr.]

Description.

Trees 3-30 m, shrubs or lianas; indumentum composed of simple trichomes, commonly absent; brachyblasts absent; branches armed with recurved or straight prickles, these scattered or aligned in raised ribs, rarely in groups of three at the leaf nodes. Stipules present, caducous. Leaves bipinnate, commonly with prickles on petioles and pinnae; extrafloral nectaries on the petiole, on the rachis between distal pairs of pinnae, and on the pinnae between distal pairs of leaflets; pinnae 1-14 pairs, opposite; leaflets 1-many pairs, opposite. Inflorescences cylindrical spikes, white, cream, yellow or red, isolated, in fascicles, or arranged in complex racemose or paniculate synflorescences. Flowers 5-merous, diplostemonous; calyx gamosepalous; corolla gamopetalous; stamens 10, anthers with a caducous apical claviform gland; pollen in tetrads or in polyads with 8, 12 or 16 grains; ovary glabrous to pubescent; stigma in a terminal pore. Fruit a flat compressed legume with thick margins, straight, usually papery. Seeds compressed, obovate to orbicular in outline, pleurogram present.

Chromosome number.

2 n = 26 [ Piptadenia retusa (Jacq.) P.G. Ribeiro, Seigler & Ebinger; Alves and Custódio (1989), as P. stipulacea (Benth.) Ducke].

Included species and geographic distribution.

Twenty-eight species in tropical America, from western and southern Mexico to southern Brazil and perhaps also at the northern limits of Argentina (Fig. 183 ).

Ecology.

Rainforests, seasonally dry tropical forests and woodlands, and riparian forests within Neotropical savannas.

Etymology.

From Greek, pipto (= to fall) and aden (= gland), in reference to the caducous anther glands.

Human uses.

Some species are used as a fodder, a source of tannins, as ornamentals, for timber, woodwork, firewood, paper and honey production, soil enrichment and ecological restoration ( Carvalho 2014).

Notes.

Piptadenia was originally broadly circumscribed to accommodate mimosoid legumes with glandular anthers, and flat, dehiscent fruits with thin valves ( Bentham 1841a; 1875). However, subsequent studies showed that this circumscription was both morphologically inaccurate and non-monophyletic. The fruits vary considerably in shape, type of dehiscence, and texture, and species once assigned to Piptadenia s.l. are placed in different groups scattered across the Mimoseae phylogeny ( Brenan 1963b; Lima and Lima 1984; Lewis and Lima 1991; Jobson and Luckow 2007; Ribeiro et al. 2018). In this context, the circumscription of Piptadenia has been narrowed by transferring species to Anadenanthera Speg., Indopiptadenia Brenan, Lachesiodendron P.G. Ribeiro, L.P. Queiroz & Luckow, Microlobius C. Presl, Newtonia Baill., Parapiptadenia Brenan, Piptadeniastrum Brenan, Pityrocarpa (Benth.) Britton & Rose, and Marlimorimia L.P. Queiroz, L.M. Borges, Marc.F. Simon & P.G. Ribeiro ( Brenan 1963b; Lima and Lima 1984; Lewis and Lima 1991; Jobson and Luckow 2007; Ribeiro et al. 2018; Borges et al. 2022), and thereby restricting Piptadenia to 28 species in the New World.

Although a densely sampled phylogeny of Piptadenia is still pending, the genus can be diagnosed by the stems armed with recurved prickles, extrafloral nectaries on the petioles, cylindrical spikes, presence of anther glands, and flat, papery, straight legumes. Three species in the genus are known to nodulate ( Faria et al. 2022).

Taxonomic references.

Brenan (1955, 1963b); Jobson and Luckow (2007); Ribeiro et al. (2018).

Figures

Figure 182. Adenopodia and Piptadenia diversity A Adenopodia gymnantha Brenan fruiting branch B fruits C Piptadenia ramosissima Benth., branch with prickles aligned along raised ribs D P. retusa (Jacq.) P. G. Ribeiro, Seigler & Ebinger, vegetative branch E, F P. micracantha Benth. E flowering branch F fruits. Photo credits A, B EOA Perez C-F LP Queiroz.

Figure 183. Distribution of Piptadenia based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.