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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

Zapoteca H.M. Hern., Ann. Missouri Bot. Gard. 73(4): 757. 1986 (publ. 1987).

Figs 204 , 205 , 206

Calliandra ser. Laetevirentes Benth., London J. Bot. 3: 97. 1844. Type not designated.

Type.

Zapoteca tetragona (Willd.) H.M. Hern. [≡ Acacia tetragona Willd.]

Description.

Erect, suberect or scandent shrubs, rarely small trees, usually unarmed, very rarely armed with spinescent stipules. Stipules leafy or rarely spinescent, usually persistent. Leaves bipinnate, usually without extrafloral nectaries, but 3 (4) species with cup-shaped or cylindrical glands on the rachis or pinnae or near the base of the petiole; pinnae 1-numerous pairs; leaflets (1) 2-numerous pairs per pinna, opposite, small (ca. 5 mm) to up to 22 cm long. Inflorescences capitate, spherical in bud and at anthesis, homomorphic, pedunculate, densely-flowered, solitary or fasciculate, arising from leaf axils, sometimes forming long, terminal pseudopanicles. Flowers bracteate, hermaphroditic or functionally staminate; calyx cup-shaped, dentate or denticulate; corolla campanulate or infundibuliform, the petals valvate in bud, usually revolute at anthesis; stamens ca. 30-60, long exserted from the corolla, 1.9-4.3 cm, always with the base fused forming a conspicuous tube, the staminal tube always included in the corolla, white, pink or red-purple, or white in the basal half and pink or red in the distal half, anthers eglandular; pollen in 16-grained polyads, acalymmate, discoid, heteromorphic, nearly always with eccentric lens-shaped thickenings on the central cells on one side of the polyad; ovary sessile or shortly stipitate, usually 10-15-ovulate, style filiform, with the stigma cup-shaped. Fruits usually pendent, linear, flattened, straight or rarely slightly curved, with thickened margins, the valves membranous or rarely coriaceous, dehiscing elastically along both margins, recurving from apex downwards. Seeds ovoid or rhomboid, usually with irregular or U-shaped pleurogram.

Chromosome number.

n = 13 ( Hernández 1986, 1989).

Included species and geographic distribution.

Twenty-two described species, all of which are restricted to the Neotropics. Its distribution extends from southern United States (southern Arizona and Texas), throughout Mexico, Central America and South America, south to Paraguay and northern Argentina, including the West Indies and the Revillagigedo Islands (Fig. 206 ). Mexico, especially the southern portion of the country, includes the richest areas in terms of species number and endemism, with 12 species, eight of which are endemic. Six species (two endemic) are distributed in Central America, and four species (one endemic) occur in the West Indies. South America harbours ten species, three of which are endemic to the Andean basin, and a further three are restricted to isolated areas in the northern Andes (Colombia, Ecuador and Peru).

Ecology.

Populations occur from sea-level to 2850 m, although most species are found at low or moderate elevations, in areas covered by seasonally dry tropical deciduous forests, and less frequently in wet forests, and even in desert or semi-desert vegetation. Seed dispersal covers short distances through the explosive dehiscing mechanism. Settling moths of the families Noctuidae , Pyralidae and Geometridae are confirmed to be the primary pollinators ( Hernández 1989).

Etymology.

Named after the Zapotec ethnic group of Oaxaca, Mexico, where a significant number of taxa occur.

Human uses.

No significant uses are known, although Z. formosa (Kunth) H.M. Hern. subsp. formosa is reported to be potentially important as a forage resource for sheep ( Newman et al. 1999).

Notes.

Detailed morphological and cytological observations supported the recognition of Zapoteca as a genus distinct from Calliandra by consistently having spherical, homomorphic, capituliform inflorescences; 16-grained, acalymmate, discoid polyads, with lens-shaped thickenings in the central grains [excluding Z. nervosa (Urban) H.M. Hern.]; cup-shaped stigmas; and a basic chromosome number of x = 13. In contrast, the Neotropical species of Calliandra are characterised by having spherical, obconic, capituliform, umbelliform or racemose, homomorphic or heteromorphic inflorescences; capitate or fungiform stigmas; 8-grained, bisymmetric, calymmate polyads with a mucilaginous basal appendage; and atypical (n = 8 and 11, rather than the x = 13 of closely related genera) chromosome numbers ( Hernández 1986, 1989; Guinet and Hernández 1989; Barneby 1998).

The pattern of differentiation within Calliandra s.l. sensu Bentam (1875) provided the basis for the segregation of the species in ser. Calliandra Laetevirentes , together with two other species placed by Bentham in his ser. Calliandra Macrophyllae ( C. aculeata and C. amazonica Benth.), into the new genus Zapoteca ( Hernández 1986, 1989). More than two decades later, in a morphological and molecular based phylogenetic analysis of Calliandra , Souza et al. (2013) supported the validity of Zapoteca as a separate genus and confirmed its monophyletic status. More recently, in a phylogenetic analysis of Zapoteca , based on nuclear and plastid DNA sequence data, Ferm (2019) and Ferm and Ståhl (2022), ratified the monophyly of Zapoteca and suggested some taxonomic rearrangements to the Hernández (1989) subgeneric classification.

Taxonomic references.

Ferm (2019); Ferm and Ståhl (2022); Hernández (1986, 1989).

Figures

Figure 204. Morphological features of the Zapoteca clade A, B Faidherbia albida (Delile) A. Chev. A habit B leaves C, D Sanjappa Calliandra cynometroides (Bedd.) E. R. Souza & M. V. Krishnaraj C habit D pinnate leaves and inflorescence in bud E Zapoteca aculeata (Spruce ex Benth.) H. M. Hern. foliage and inflorescences at anthesis (Neill 18437) F Zapoteca formosa subsp. schottii (Torr. ex S. Watson) H. M. Hern. habit and dehisced fruits G Viguieranthus glaber Villiers leaves and inflorescences post-anthesis. Photo credits A Gobabeb - Namib Research Institute B Dave U C, D G Suresh E D Neill F D Beckman G C Davidson.

Figure 205. Inflorescence and fruit morphology in the Zapoteca clade A, B Faidherbia albida (Delile) A. Chev. A inflorescences at anthesis B indehiscent fruit C, D Sanjappa Calliandra cynometroides (Bedd.) E. R. Souza & M. V. Krishnaraj C inflorescence post-anthesis D pinnate leaves and immature fruit E Thailentadopsis tenuis (Craib) Kosterm. inflorescence F Viguieranthus perrieri (R. Vig.) Villiers inflorescence at anthesis G Viguieranthus alternans (Benth.) Villiers foliage and fruits before dehiscence H Viguieranthus brevipennatus Villiers inflorescence at anthesis (Randrianarivony 175) I Zapoteca tetragona (Willd.) H. M. Hern. inflorescence at anthesis J Zapoteca portoricencis (Jacq.) H. M. Hern. subsp. portoricensis inflorescence at anthesis (Amith 74438) K Zapoteca formosa subsp. schottii (Torr. ex S. Watson) H. M. Hern. dehisced fruit. Photo credits A S Piry B B Adkins C, D G Suresh E https: // marketingoemoffice. com / Data _ Pithecellobium. html F F Ratovoson G F Rakotoarivony H T Randrianarivony I FJ Gomez Marin J J Amith K D Beckman.

Figure 206. Distribution of Zapoteca based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.