Ricoa Duno & Torke, PhytoKeys 205: 294. 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

Ricoa Duno & Torke, PhytoKeys 205: 294. 2022.

Figs 217 , 222

Type.

Ricoa leptophylla (DC.) Duno & Torke [≡ Acacia leptophylla DC.]

Description.

Xerophytic shrubs 0.2-1.5 m, often growing in patches several meters in diameter. Stipules straight to recurved spines, persistent. Leaves bipinnate, extrafloral nectaries subsessile or shortly stipitate, circular, between the first pinnae pair (sometimes also between the second pair), absent on the pinnae; pinnae 3-7 (9) pairs; leaflets 8-25 pairs, opposite, venation weakly developed, nearly simple or 1-branched, subcentric. Inflorescences capitula, arising from brachyblasts. Flowers sessile, mostly homomorphic but some functionally staminate, 5-merous; calyx campanulate, teeth ovate or deltate; corolla tubular, lobes ovate, recurving; stamens 40-76; intrastaminal callosities developed, sometimes obscure or wanting in staminate flowers; polyads 16-celled, more or less isodiametric; ovary slenderly ellipsoid, compressed, shortly stipitate. Fruits falcately or subcircinnately broadly linear fruits, the valves stiffly leathery, at first plano-compressed, becoming turgid and low-convex (on both faces of legume) over each seed, indistinctly venulose, the cavity continuous, dehiscence inert through both sutures. Seeds obliquely descending, compressed-lentiform, funicle straight or sinuous (but not sigmoid), testa smooth, hard, moderately lustrous, dark castaneous, the pleurogram incomplete.

Chromosome number.

Unknown.

Included species and geographic distribution.

Monospecific ( R. leptophylla ), endemic to Mexico, widely scattered over the Central Mexican Plateau (Fig. 222 ).

Ecology.

Ricoa leptophylla grows in dry or semi-arid grasslands and thornscrub, extending into the lower edge of the pine-oak belt, on both basaltic and calcareous substrates, at 1600-2800 m.

Etymology.

The generic name honours María Lourdes Rico, whose profound dedication and unrelenting commitment to botanical research over decades has deeply enhanced knowledge and understanding of the Leguminosae , especially of the ingoid clade.

Notes.

Ricoa was segregated from Painteria to account for the non-monophyly of that genus ( Tamayo-Cen et al. 2022). The genus is morphologically similar to Painteria and geographically sympatric with that genus, and is distinguished by a set of quantitative leaf and flower traits.

The common name for R. leptophylla is Huisache, a name that is also applied to Vachellia farnesiana (L.) Wight & Arn. and other related species with spinescent stipules ( Barneby and Grimes 1996). Other common names are charrasquillo, gatuña, and tehuixtle ( Calderón de Rzedowski 2007).

Taxonomic references.

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