Piptadeniopsis Burkart, Darwiniana 6: 478. 1944.

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

Piptadeniopsis Burkart, Darwiniana 6: 478. 1944.

Fig. 156

Type.

Piptadeniopsis lomentifera Burkart

Description.

Shrub or small branched treelet 3-7 m, shoots striate, green for first two years, terminal shoots often slender and somewhat pendulous, armed with 1-3 mm long stipular spines at nodes. Leaves bipinnate, small, borne on short axillary tuberculous brachyblasts or alternate on older growth; petiole 3-10 mm long, puberulent, terminating in a caducous spicule; sessile, circular nectaries at point of insertion of pinnae and 1-2 minute sessile nectaries at insertion of distal leaflet pairs; pinnae 1 pair, leaflets (2) 3 pairs, elliptic-obovate, obtuse and emarginate at apex, weakly asymmetric at base, glabrous or sparsely pubescent, 3-4-veined. Inflorescence capitate, solitary, axillary on 1 cm peduncles; bracteoles subtending each flower rhomboid, acuminate, incurved, caducous. Flowers uniformly hermaphrodite; sepals valvate, fused to form a cupular calyx, villous; petals valvate, almost free at anthesis, villous; stamens 10, free, anthers with a minute stipitate spherical gland apical on the connective; pollen in columellate 8-12 (16)-grained polyads, the individual grains with porate apertures; ovary stipitate, pubescent, stigma punctate, inconspicuous. Fruits stipitate, true loments, breaking up into 3-9 one-seeded articles with no persistent replum, linear, straight, compressed, margins raised, to 8 cm long × 0.8-1 cm wide, valves sub-coriaceous, glabrous. Seeds very compressed, ovate, 7 × 7 × 1 mm, wingless, testa thin, pleurogram absent.

Chromosome number.

2 n = 28 ( Luckow et al. 2005).

Included species and geographic distribution.

Monospecific ( P. lomentifera ), endemic to the Chaco domain in Paraguay and south-eastern Bolivia (Fig. 156 ).

Ecology.

Tropical and subtropical seasonally dry thorn forest and Chaco woodland. Usually deciduous.

Etymology.

From - opsis (Greek = appearance) and Piptadenia , another genus of mimosoid legume.

Human uses.

Unknown.

Notes.

Piptadeniopsis is robustly supported as sister to Prosopidastrum and these two genera together with Mimozyganthus form a subclade (Fig. 143 ; Luckow et al. 2005; Koenen et al. 2020a; Ringelberg et al. 2022). Piptadeniopsis and Propidastrum both have photosynthetic stems with longitudinal striations, whereas the stems of Mimozyganthus are terete. The two former genera also share lomentiform fruits while those of Mimozyganthus are plano-compressed, marginally winged and single-seeded. Piptadeniopsis has pollen in polyads whereas Mimozyganthus and Prosopidastrum have monads.

Taxonomic references.

Burkart (1944), including illustration; Luckow et al. (2005).

Figures

Figure 143. Generic relationships in the Dichrostachys clade (tribe Mimoseae). Note that the non-monophyly of Dichrostachys and Alantsilodendron has been simplified in this figure (see Suppl. material 2). For description of phylogeny and support values, see Fig. 6 caption (page 63).

Figure 156. Distribution of Piptadeniopsis based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.