A new Spathiphyllum (Araceae) from Mexico segregated by its morphology and floral scent from closely related species

Spathiphyllum is a mostly Neotropical genus of the Araceae plant family. Many species have a long flowering period and emit a strong, pleasant, and species-specific floral scent. In Mexico, Spathiphyllum is represented by 14 species, 9 of which are endemic. Here, we describe the morphology, floral scent composition, and flowering phenology of a hitherto unknown species, S. hentrichianum sp. nov. This species is characterized by having a petiole not sheathed to the geniculum, leaf blades with less than 25 primary lateral veins per side, 1–2 ovules per locule, and 3–5 ovules per ovary. The strong scent consists of various terpenes and aromatic compounds, mainly (E,E)-α-Farnesene, (E)-Cinnamyl acetate and (E)-Cinnamyl alcohol. The new species is morphologically similar to S. cochlearispathum, but the latter differs in having a petiole sheathed to the geniculum, leaf blades with up to 31 primary lateral veins per side, 2–6 ovules per locule and 6–16 ovules per ovary, and the floral scent is also different between both species. In S. cochlearispathum, the scent is dominated by aromatic compounds, one terpene and one nitrogen-containing compound, such as Methyl salicylate, Methyl p-anisate, Methyl (E)-cinnamate, (R)-Linalool and 2-Phenylacetonitrile. The flowering cycle of an inflorescence in S. hentrichianum lasted between 25 and 29 days. We suggest that detailed volatile organic compounds in the floral scent could be useful when defining a new taxon, especially among cryptic and sympatric aroid species.