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| Struthanthus ibe-dzi Mald. & Cerros, in Maldonado-Borja, Cerros-Tlatilpa et Galván-González, 2023. |
Abstract
Struthanthus ibe-dzi sp. nov. is a new species described and illustrated from the cloud and pine-oak forests of the Sierra Madre del Sur in Oaxaca, Mexico. This species shares similarities of leaf shape and inflorescence type with S. deppeanus, S. quercicola, and S. ramiro-cruzii. However, S. ibe-dzi can be recognized by its glaucous branches, leaves and inflorescences; compressed nodes; convoluted distal half of styles in pistillate flowers; and staminate flowers with asymmetrical thecae and an extended connective forming an apiculate horn in both anther series. A distribution map and an identification key are provided to separate S. ibe-dzi from morphologically similar congeners present in the region.
Keywords: Endemic, hemiparasitic, mistletoes, taxonomy
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| Struthanthus ibe-dzi (Loranthaceae) A base of stem and disk of secondary haustoria (sh) B epicortical root (er) and swollen stem of host plant by the penetration of secondary haustoria (sh) C staminate inflorescences with caducous bracts (bra) and bracteoles (brc) D dissected petals of staminate flower showing two series of stamens (S1, S2), with anthers in the lower series (S1) displaying a prominent connectival horn (cn); receptacle showing an undifferentiated pistilloid and a nectary (ne) surrounded by the calyculus E pistillate inflorescences and compressed node (arrow) F dissected pistillate flower showing vestigial staminodes (st) opposite to petals, and an inferior ovary with convoluted style and calyculus (ca) G upper view of ovary in a pistillate flower showing its calyculus (ca) and nectary (ne) H immature fruits crowned by the calyculus. |
Struthanthus ibe-dzi Mald. & Cerros, sp. nov.
Diagnosis: Struthanthus ibe-dzi morphologically resembles S. deppeanus and S. quercicola in having epicortical roots on stems, similar leaf shapes, and inflorescences in racemes. However, the new taxon differs by its compressed nodes, stems, leaves, and inflorescence glaucous; leaf blade with base cuneate to oblique; staminate flowers 6–9 mm long with asymmetrical thecae and an extended horn-shaped apiculate connective in both anther series; and pistillate flowers with distally convoluted styles.
Etymology: The epithet ibe-dzi refers to the common name given to any mistletoe in Zapotec language (Ibë-dzí) in the San Juan Mixtepec region, which means “hair(s) on top of”, where “ibé” denotes “hair(s)” and “dzi” indicates “on top of”.
Maria Guadalupe Maldonado-Borja, Rosa Cerros-Tlatilpa and Luis Gil Galván-González. 2023. A New Species of Struthanthus Mart. (Loranthaceae) from Oaxaca, Mexico. PhytoKeys. 225: 69-81. DOI: 10.3897/phytokeys.225.101238
Struthanthus ibe-dzi sp. nov., es una nueva especie descrita e ilustrada de los bosques de niebla y de pino-encino de la Sierra Madre del Sur en Oaxaca (México). La nueva especie se puede confundir con S. deppeanus, S. quercicola, y S. ramiro-cruzii por la forma de la hoja y el tipo de inflorescencia. Sin embargo, S. ibe-dzi se distingue por sus ramas, hojas e inflorescencias glaucas; sus nodos comprimidos; flores pistiladas con el estilo convoluto desde la mitad hacia la parte distal; y flores estaminadas con tecas asimétricas y un conectivo extendido apiculado en forma de cuerno en la serie baja de las anteras. Se incluye un mapa de distribución y una clave de identificación para separar S. ibe-dzi de sus congéneres regionales morfológicamente similares.