P. ser. Impolita ser. nov.
TYPE: P. strictum G.S. Bunting
Internodia brevia; cataphylla persistentia; petiolus teres vel D-formatus; lamina palida adaxialiter, glaucescens.
Etymology: From impolitus meaning unpolished, i.e. matte in reference to the matte and pale lower blade surfaces.
Three Central American taxa, P. hebetatum, P. strictum, and P. thalassicum and at least one additional undescribed species from South America belong in this group. It is characterized by having leaf blades dark to medium green above but very pale, almost white beneath and covered with a minute waxy covering making the surface matte. The species has relatively short internodes, persistent cataphylls which often dry yellowish or have patches of yellowish epidermis persistent (not always true for P. thalassicum). Petioles may be obtusely somewhat flattened to D-shaped and dry with a yellowish epidermis (not always true for P. thalassicum). Blades are ovate-cordate to ovate-triangular.