ИСТИНА

The palynological samples were collected from borehole №1 which is located in North East part of Moscow. The Bathonian stage (Middle Jurassic) is dated based on miospores presence of Neorastrickia and ancient coniferous pollens of Alisporites oblatinoides. Gleicheniaceae miospores (Plicifera and Gleicheniidites) had been comprehensively studied with a light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The Gleicheniidites laetus miospores are characterized by rounded-triangular shapes (23 - 26 µm in diameter). The laesura is open and almost reaches to equator. The distal kyrtoms are clearly met. Exosporium thickening (1-2 µm) could be weakly observed along the equator. Plicifera delicata is characterized by rounded-triangular outlines of spores (25 - 30 µm in diameter) with distal kyrtoms and psilate exosporium. Its laesura is split at the ends of rays. It is very difficult to find the equatorial thickening on equatorial view with LM for two above-mentioned species. This feature has beeninvestigated at the spores of Plicifera delicata and Gleicheniidites laetus using a SEM. The equatorial thickening has been discovered at the both species. The sporoderma of studied species has been also carried out with a TEM. The exosporium of the both species is one-layered, homogeneous. The sporoderma depressions observed on the spore surface using a SEM are reflected in thinner regions of the spore wall (0,4 - 0,7 µm) in TEM. The exosporium of laesura section is one-layered too, homogeneous, though it becomes slightly thicker at the base of the layer and bifurcates at their ends. Unfortunately individual middle layer near the laesura could not be found at the both species, whereas it was discovered into the exosporium of modern Gleicheniaceae ferns and the Carboniferous Oligocarpia kepingensis. Probably, due to the bad preservation of the studied spores caused such difference.