Programinis burmitis gen. et sp. nov., and P. laminatus sp. nov., Early Cretaceous grass-like monocots in Burmese amber

Abstract

The remains of a spikelet and a leaf of an Early Cretaceous grass-like monocot in Burmese amber are described as Programinis burmitis gen. et sp. nov., and P.�laminatus sp. nov., respectively. The laterally compressed spikelet of P.�burmitis has two basal sterile glumes, a series of lemmas and paleas and remains of stamens and a gynoecium. Adjacent to the spikelet are spherical, monoporate pollen grains. The epidermis of the leaf fragment of P.�laminatus contains numerous stomata with well-defined, sausage-shaped guard cells with elongate nuclei, rows of epidermal cells with long and short cells and spherical and elliptical silica-like bodies in cuboid epidermal cells. Unpointed papillae and uniseriate bicellular microhairs, both raised, occur on the leaf surface. Programinis burmitis and P.�laminatus are considered early bambusoid types that grew in tropical, forested habitats. Their discovery suggests that true grasses may have evolved in South-east Asia, since the Burmese amber mines are located on the Burma Plate, part of Laurasia.