Additional fossil specimens of Eophylica (Rhamnaceae) in mid-Cretaceous amber from the Hukawng Valley, Myanmar

Abstract

The recently described fossil angiosperm genus Eophylica (Rhamnaceae) was based on 18 amber-embedded specimens derived from two sites in northern Myanmar. A vegetatively similar fossil, which came from the same amber mines but which lacked flowers, had been previously described as a putative green alga and given the name Electrophycus. The dimensions and vegetative aspect of that taxon’s holotype specimen are identical with those of the Eophylica fossils. Four additional specimens were acquired by the senior author after the publication of Electrophycus, all of which have a single terminal flower that is either immature or essentially fully formed. Using techniques of floral dissection, high magnification microscopy, and microphotography of the better-developed flowers, we present a more detailed picture of the floral organs, especially the stamens and style, of Eophylica. These flowers differ from the holotype specimen of Eophylica and 3 of its paratypes in that they possess involucral bracts of a so-called ‘pseudanthial head,’ a structure that the authors of Eophylica had only ascribed to certain other paratype specimens of the genus.