Lachesiodendron P.G. Ribeiro, L.P. Queiroz & Luckow, Taxon 67(1): 45. 2018.

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

Lachesiodendron P.G. Ribeiro, L.P. Queiroz & Luckow, Taxon 67(1): 45. 2018.

Figs 168 , 169 , 170

Type.

Lachesiodendron viridiflorum (Kunth) P.G. Ribeiro, L.P. Queiroz & Luckow [≡ Acacia viridiflora Kunth]

Lachesiodendron has an isolated position in the Mimoseae phylogeny, between the Parkia clade and the node including the Mimosa , Stryphnodendron and Ingoid clades ( Koenen et al. 2020a; Ringelberg et al. 2022; Fig. 168 ). Because Lachesiodendron is not resolved with any of these clades, it is here treated as a distinct, monospecific lineage within Mimoseae .

Description.

Trees (2) 3-20 m; indumentum puberulent to rarely glabrous; brachyblasts absent; branches armed with stipules modified into lignified spines, down-curved, paired at branch nodes, prickles absent, lenticels present. Stipules spinescent. Leaves bipinnate, unarmed; extrafloral nectaries on the petiole, on the leaf rachis between distal pairs of pinnae, and on the pinnae between distal pairs of leaflets; pinnae 5-15 pairs, opposite or sub-opposite; leaflets 20-50 pairs, opposite. Inflorescences 1-2 (3) axillary spikes. Flowers 5-merous, yellowish green; calyx gamosepalous, campanulate; corolla gamopetalous, cylindrical; stamens 10, anthers with a short-stipitate caducous apical gland; pollen in 8-grained polyads; ovary glabrous, long stipitate, exserted from the corolla, stigma in a terminal pore. Fruit a flat-compressed legume with thick margins, straight, not constricted between the 8-10 seeds, valves thin, coriaceous. Seeds ovate to obovate with a U-shaped pleurogram on both faces (Fig. 169 ).

Chromosome number.

Unknown.

Included species and geographic distribution.

Monospecific ( L. viridiflorum ), in tropical America, disjunctly from southern and western Mexico to northern Argentina (Fig. 170 ).

Ecology.

Confined to seasonally dry tropical forests and woodlands.

Etymology.

From ' Lachesis ', in reference to the bushmaster viper [ Lachesis muta (Linnaeus, 1766)] whose vernacular name (surucucu) is also applied to the tree in Brazil, probably because the pair of nodal spines resembles the viper’s fangs (Fig. 169 ), and - dendron (Greek = tree).

Human uses.

Lachesiodendron viridiflorum is used as fodder, for the timber, for environmental restoration, and provides good quality firewood and charcoal ( Carvalho 2014). The species could be used for beekeeping, as it produces abundant nectar, and is potentially medicinal due to the presence of tannins in the bark ( Carvalho 2014).

Notes.

Lachesiodendron was recently described by Ribeiro et al. (2018) to accommodate a single species of Piptadenia that did not group with the remainder of the genus, or with any other mimosoid genera in phylogenetic analyses ( Jobson and Luckow 2007; Simon et al. 2011, 2016; Ribeiro et al. 2018). This circumscription is supported by an unusual combination of morphological characters: stipules modified into lignified spines; absence of prickles; 1-2 (3) spikes 20-22 mm in diameter at anthesis, in fascicles in the axils of coevally developing leaves; cylindrical corolla, much longer than the calyx; unusual greenish flowers which gave rise to the species epithet Lachesiodendron viridiflorum ; polyads with 8 grains arranged in two opposing tetrads ( Ribeiro et al. 2018).

Taxonomic references.

Ribeiro et al. (2018).

Figures

Figure 6. Generic relationships in tribe Ceratonieae. Left part of figure shows complete genus-level Caesalpinioideae phylogeny with the Ceratonieae indicated with a red rectangle. Branch lengths are expressed in coalescent units and terminal branches were assigned an arbitrary uniform length for visual clarity. Support for relationships is based on fractions of supporting and conflicting gene trees: pie charts show gene tree support and conflict per node (blue representing supporting gene trees, green gene trees supporting the most common alternative topology, red gene trees supporting further alternative topologies, grey gene trees uninformative for this node), and numbers above pie charts are Internode Certainty All support values [both calculated with PhyParts (Smith et al. 2015)]. If present, red numbers below pie charts are non-significant (i. e.> 0.05) outcomes of ASTRAL's polytomy test (Sayyari and Mirarab 2018), which tests for each node whether the polytomy null model can be rejected. Monophyletic genera are represented by single branches; see Suppl. material 2 for a phylogeny with all accessions. See Suppl. material 3 for gene tree support across the phylogeny. The phylogeny is a pruned version of the backbone phylogeny of Ringelberg et al. (2023), where full details of the data and phylogenomic analysis methods are presented.

Figure 168. Phylogenetic relationships of Lachesiodendron in tribe Mimoseae. For description of phylogeny and support values, see Fig. 6 caption (page 63).

Figure 169. Lachesiodendron viridiflorum (Kunth) P. G. Ribeiro, L. P. Queiroz & Luckow A habit B inflorescence C pair of persistent spinescent stipules D fruits. Photo credits A, C, D PG Ribeiro B LP Queiroz.

Figure 170. Distribution of Lachesiodendron based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.