LEÑOS FOSILES DE DICOTILEDONEAS DEL PALEOCENO DE PATAGONIA, ARGENTINA

Abstract

The first Myrtaceous wood described from Argentine sediments of Patagonia is studied in this paper. It was found in the region of Puesto Alvarez (south east part of the Chubut province) in beds of the Salamanca Formation. The most important anatomical characters are: 1) Diffuse porosity; 2) Pores mostly solitary, very numerous and small, 3) Perforation plates simple; 4) Intervascular pitting small, alternate and vestured; 5) VesseLray pits elongated to gash-Iike, vestured; 6) Rays very Iow and heterocellular, predominantly biseriates, uniseriates apparently composed of upright cells, 7) Parenchyma apotracheal diffuse tending to link in short tangential chains; 8) Disjunctive cells in axial and radial parenchyma; 9) Fibre tracheids with distinctly bordered pits; 10) Vasicentric tracheids presento Comparisons have been made with fossil and extant 1yrtaceae, concluding tbat it has differences with al! of tbem, but is more related to the living, exclusively South American genus Myrceugenia. The present fossil is considered, therefore, as a new species, named Myrceugenia chubutense on account of the place where it was found.