Hesperalbizia Barneby & J.W. Grimes, Mem. New York Bot. Gard. 74(1): 112. 1996.

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

Hesperalbizia Barneby & J.W. Grimes, Mem. New York Bot. Gard. 74(1): 112. 1996.

Figs 212 , 213

Type.

Hesperalbizia occidentalis (Brandegee) Barneby & J.W. Grimes [≡ Albizia occidentalis Brandegee]

Description.

Unarmed trees 20 (30) m, bark pale silvery grey. Stipules small, membranous, caducous, cordate at base. Leaves bipinnate; extrafloral nectaries below mid-petiole, sometimes close to the base, sessile, round or elliptical, shallowly concave, commonly smaller ones at the tip of the petiole and the rachis of the pinnae; pinnae 3-8 pairs; leaflets 5-10 pairs per pinna, venation pinnate. Inflorescence 5-20-flowered capitula, receptacle subglobose, spherical, arising either singly or fasciculate. Flowers sessile, homomorphic, 5-merous; calyx campanulate, lobes ovate or short-deltate; corolla narrowly vase-shaped; stamens 52-76, 20-24 mm long, joined at base into a well exserted, 5-11 mm long tube; pollen in 16-celled polyads, more or less isodiametric; ovary linear-elliptic, glabrous, stipitate, style shortly exserted, slightly dilated at tip. Fruits solitary or paired, broad-linear plano-compressed, long-stipitate, 8-12 (13)-seeded, inertly dehiscent through both sutures. Seeds transverse, compressed discoid or oblong-ellipsoid, areolate, funicle filiform; testa crustaceous, brown, and lustrous; pleurogram closed.

Chromosome number.

2 n = 26 (Rico Arce 1992).

Included species and geographic distribution.

Monospecific ( H. occidentalis ), widely distributed in western and southern Mexico (Fig. 213 ).

Ecology.

Largely confined to seasonally dry tropical deciduous forests and woodlands, from sea level to 1500 m elevation, locally abundant in tropical and marginally subtropical western Mexico. Strongly deciduous, fruits long-retained on leafless trees, flowering preceding or coinciding with new leaf flush at the end of the dry season. Seed dispersal passive.

Etymology.

Greek = hesperos, the evening star, and by extension the West, plus the generic name Albizia in reference to the westerly distribution of H. occidentalis within Mexico and its previous placement in the genus Albizia .

Notes.

The plano-compressed, stiffly papery fruits of H. occidentalis are very similar to the fruits of some species of Pseudalbizzia and Albizia , from which Hesperalbizia was segregated by Barneby and Grimes (1996). However, recent phylogenies have demonstrated that Hesperalbizia is not closely related to Albizia or Pseudalbizzia , but is instead sister to Lysiloma ( Duno et al. 2021; Peraza et al. 2022; Ringelberg et al. 2022). Hesperalbizia can be distinguished from species of Pseudalbizzia and Albizia by the absence of a modified central flower, leaflets with pinnate (not palmate-pinnate) venation, peripheral flowers sessile, and seed ovate-circular and areolate.

Taxonomic references.

Barneby and Grimes (1996).

Figures

Figure 212. Morphology of Cojoba clade A-C Cojoba arborea (L.) Britton & Rose A habit B leaves C fruit D Cojoba graciliflora (S. F. Blake) Britton & Rose in Mexico, fruit E-G Hesperalbizia occidentalis (Brandegee) Barneby & J. W. Grimes E habit F trunk G leaves and fruits H Lysiloma candidum Brandegee, habit l Lysiloma acapulcense (Kunth) Benth. fruit J-N Lysiloma latisiliquum (L.) Benth. J habit K trunk L leaves and stipule M flowers N fruit O, P Lysiloma tergeminum Benth., fruits. Photo credits A-C GA Romero Gonzalez D, J-N R Duno de Stefano E-I, O, P CE Hughes.

Figure 213. Distribution of Hesperalbizia based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.