The sub-arborescent lycopsid Omphalophloios feistmantelii (O. Feistmantel) comb. nov. emend. from the Middle Pennsylvanian of the Czech Republic

Abstract

About ninety compression specimens of sub-arborescent lycopsid Sporangiostrobus feistmantelii (Feistmantel) Němejc from the middle Westphalian strata of central and western Bohemia, Czech Republic, were studied. A new combination, Omphalophloios feistmantelii (O. Feistmantel) comb. nov. emend., is proposed and the original diagnosis is emended, mainly by new data concerning spores, sporangia, vegetative and reproductive parts. The basal vegetative part of the stem bears rhomboidal leaf cushions with bell-shaped leaf scars, although a larger part of the stem consists of a fertile axis bearing oval sporangia about 5–6mmwide and 7–8mmlong. O. feistmantelii is estimated to be a plant of about 2 to 3 m in height of columnar habit sometimes once or twice dichotomizing in the fertile part of the stem. The fertile zone matured from bottom to top shedding first more than 20 cm long grass-like laminae and than ripened sporangia, leaving only pedicels on the naked axis (Puertollania-disarticulation stage). This suggests continuous reproduction from the time the plant reached the mature stage at the end of its life cycle. The older decorticated part of the stem displays the Knorria-type of preservation. In situ microspores possess large morphological variation and can be assigned to the genera Densosporites (Berry) Butterworth et al. and Cristatisporites (Potonié & Kremp) Butterworth et al. In situ megaspores are of the Zonalesporites superbus-type. The stratification of sporangial walls is described from cuticle studies. O. feistmantelii is interpreted as a plant having an opportunistic life strategy and was able to colonize rapidly local habitats, particularly where there was limited competition, preferring peat and mixed peat-clastic swamps.