Abstract

LOZANO, Evangelina; AQUINO, Víctor  and  ZAPATER, María. Comparative morphology in Lithraea (Anacardiaceae), vegetative and reproductive aspects and distribution in Argentina. Lilloa [online]. 2022, vol.59, n.1, pp.51-72. ISSN 0075-9481.  http://dx.doi.org/https://doi.org/10.30550/j.lil/2022.59.1/2022.04.06.

The genus Lithraea Miers ex Hook. & Arn. is represented in Argentina by Lithraea molleoides and L. brasiliensis, the former in the Chaqueña Biogeographic Province (PB), Oriental and Serrano Districts, also in the Paranaense PB and marginal forests. L. brasiliensis is limited to Misiones in the PB Paranaense. The differentiation of the species suggested by various authors is considered imprecise and based on a single character. No recent taxonomic, morphological and reproductive biology studies were found from Argentina. The objectives were to expand the morphological characteristics of the taxa in a comparative way; determine the sexuality, reproductive success and germination potential of L. molleoides in a population of Salta; also to map the recorded distribution of the species. The studied specimens belong to the collections of the CTES, LIL, MCNS, SI herbaria and to virtual Herbaria in Jstor Global Plants. Observations were made with OM and SEM. The material was described and illustrated. The diagnostic characters for the determination of the taxa were foliar (type, shape, apex, margin, number of nerves, consistency), some floral; also anatomical of the fruit. Germination experiments were carried out, after an imbibition test that evaluates the presence physical dormancy (DF), cited for the Anacardiaceae Family among others, and on that basis, decide the possible treatments to apply for the determination of the PG. Viability was estimated from the sum of germinated and non-germinated seeds with white and turgid embryos considered viable, which is used as a supplement procedure to the tetrazolium test when it is not performed. The differential morphological characters among species are clear, varied and consistent. In the population of L. molleoides from the Serranía del Gallinato, La Caldera department, province of Salta, the plants are diclino-dioecious, with probable apomixis and low reproductive success. Low imbibition per- centage was recorded, very low viability in the seed-fruits and therefore a reduced to almost zero germination rate. A wide disjunct distribution of L. molleoides and a very reduced distribution of L. brasiliensis were mapped in Misiones.

Keywords : Germinative power; Lithraea; taxonomy.

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