PlantaeDB Logo
Login Sign-up

Genus Lysiloma in Subfamily Caesalpinioideae

In botanical taxonomy, a genus (plural genera) is a rank used to group closely related species within a family. In the hierarchy, genus sits below family and above species.

Genera are defined by shared morphological, anatomical, and genetic characteristics (for example, features of flowers, fruits, seeds, or leaves) that indicate a close evolutionary relationship among the species they contain.

Each genus can include one or more species. Examples include Rosa (roses) and Solanum (nightshades, including tomato and eggplant).

Do you wish to read more about plant taxonomy? Click here!

Genus Description

Suggest a correction!

Lysiloma (Benth.) lies in subfamily Caesalpinioideae of Fabaceae, a mimosoid lineage close to Acacia and Leucaena. The genus comprises approximately 10 species in current treatments, ranging from the southwestern United States to northern South America and widely across the Caribbean, occupying tropical dry forest, coastal scrub, and anthropogenic edges. Lysiloma latisiliquum (L.) Benth. is the long‑standing type (ILDIS, 2010; POWO, 2024).

Mimosoid habit and architecture differentiate the genus: unarmed trees or shrubs bearing bipinnate leaves with paired stipules (well developed in L. microphyllum), leaflets in several to many pairs, and usually a prominent terminal pair. Inflorescences are spherical heads or elongate spikes; the corolla is funnel‑shaped with a tubular hypanthium, stamens are exserted, and nectaries are often present. The ovary is superior with axile placentation and numerous ovules; the fruit is a flattened, oblong to strap‑shaped, dehiscent or tardily dehiscent pod bearing many compressed seeds. Irizarry et al. (2013) treated this suite of traits as diagnostic of Lysiloma.

The main centers of diversity are Mexico (including the Yucatán Peninsula) and the Greater Antilles, with secondary presence in Central America and northern South America; regional richness peaks in seasonally dry habitats up to moderate elevations. Biogeographic patterns reflect Caribbean–Mesoamerican affinities with some narrow endemics (e.g., L. acapulcense in the Pacific Mexican slope; Irizarry et al., 2013). Reproductive biology is typical of mimosoids: bee pollination is strongly inferred from floral morphology; fruit structure supports endozoochory or hydrochory depending on setting (Lewis et al., 2005). Chromosome base numbers remain incompletely established and are not here cited without direct confirmation.

Taxonomically, Lysiloma has long been treated as monophyletic within the informal “Leucaena group” of the mimosoid clade (Hughes et al., 2003; Barneby & Grimes, 1996). Modern subgeneric frameworks are not consistently applied; sectional treatment remains uncertain. Species limits and synonymy have been revised (Irizarry et al., 2013), with variation among checklists: WFO (2024) lists L. divaricatum as distinct, whereas ILDIS (2010) subsumed it under L. latisiliquum. Recent molecular phylogenies place Lysiloma near Acacia sensu stricto and Vachellia, reinforcing its generic distinctness but revealing incompletely resolved relationships at deeper levels (Miller et al., 2017).

Humans use the group mainly as ornamentals and shade trees in xeric landscapes; L. latisiliquum and L. candidum are cultivated regionally for hedgerows and street planting (Nicolson et al., 1991). There are minor timber applications (Johnson & Brakensiek, 1991), but none of the species is a major crop or invasive.

Conservation assessments vary across checklists and are often hampered by synonymy. Irizarry et al. (2013) noted local pressures on Caribbean endemics, yet broad‑scale listings lack precision. Taxonomic clarity and field inventories are needed to target protection effectively; ongoing phylogenomic work (Miller et al., 2017) promises refined species boundaries and biogeographic understanding.

Pick a Species to see its components: