Gretheria Duno & Torke, PhytoKeys 205: 292. 2022.

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

Gretheria Duno & Torke, PhytoKeys 205: 292. 2022.

Figs 217 , 221

Type.

Gretheria sonorae (S. Watson) Duno & Torke [≡ Pithecellobium sonorae S. Watson]

Description.

Arborescent shrubs and small, often multi-stemmed trees, 2-14 m. Stipules stout, recurved, early lignescent, spinescent, these persistent on shoots and trunks long after leaves are shed. Leaves bipinnate, extrafloral nectaries at or below the midpoint of the petiole, sessile, shallow-cupular, thick-rimmed or plane and dimpled; pinnae 1-6 (13) pairs; leaflets 10-31 pairs per pinna, opposite, venation pinnate, the midrib slightly displaced, giving rise on each side to 2-5 weak secondary veins. Inflorescences capituliform racemes arising from brachyblasts. Flowers sessile, homomorphic, 5-merous; calyx deeply campanulate; corolla subcylindrical, lobes erect, white-silky strigose dorsally; stamens 40-52; pollen in 16-celled polyads, more or less isodiametric; intrastaminal disc 5-lobed or simple callosities; ovary ellipsoid, shortly stipitate. Fruits oblong, contracted, body straight or almost straight, plano-compressed legumes, the valves bluntly framed by longitudinally 3-ridged sutures, stiff, somewhat brittle, brownish-green, externally veinless, glabrous, red-granular or both granular and puberulent outside, the cavity continuous. Seeds transverse, compressed, disciform to orbicular in outline, funicle dilated, sigmoid, pleurogram U-shaped.

Chromosome number.

Unknown.

Included species and geographic distribution.

Two species, disjunctly scattered along the Pacific coast of Mexico, from Sonora south to Central America (Honduras, Nicaragua, and northwestern Costa Rica) (Fig. 221 ).

Ecology.

Tropical dry forests, thorn scrub and brush-woodlands, from sea level to 400 m elevation, occasionally to 700 m.

Etymology.

The generic name honours Rosaura Grether González, a Mexican botanist.

Notes.

Gretheria was segregated from Havardia by Tamayo-Cen et al. (2022) to account for the non-monophyly of Havardia , and is differentiated from Havardia by flowers with a longer calyx with shorter lobes, the corolla deeply campanulate with erect lobes, and a five-lobed nectary disc or callosities surrounding the ovary (in Havardia absent or thickened callosities).

Taxonomic references.

Barneby and Grimes (1996); Britton and Rose (1928); Calderón de Rzedowski (2007); Tamayo-Cen et al. (2022).

Figures

Figure 217. Morphology of selected species of the Pithecellobium clade A Ebenopsis ebano (Berland.) Barneby & J. W. Grimes, fruit B, C Havardia albicans (Kunth) Britton & Rose B leaves C inflorescence D Gretheria campylacantha (L. Rico & M. Sousa) Duno & Torke, fruit E Ricoa leptophylla (DC.) Duno & Torke, inflorescence and young flowers F Painteria elachistophylla (A. Gray ex S. Watson) Britton & Rose, fruit G Pithecellobium dulce (Roxb.) Benth. habit H Pithecellobium unguis-cati (L.) Benth. inflorescence I Pithecellobium lanceolatum (Humb. & Bonpl. ex Willd.) Benth. pod and seeds J Pithecellobium winzerlingii Britton & Rose pod and seed K Sphinga acatlensis (Benth.) Barneby & J. W. Grimes flowers L Sphinga platyloba (Bertero ex DC.) Barneby & J. W. Grimes flowers. Photo credits A, E, F, H R Duno de Stefano B, C, J GA Romero Gonzalez D, I, K CE Hughes G D Pedersen L C Ramirez.

Figure 221. Distribution of Gretheria based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.