Maderas gimnospérmicas de la Formación Solca (Pérmico Inferior), provincia de La Rioja, Argentina

for the first time gymnospermous woods from the solca formation (lower permian) from the olta and parque guasamayo localities are described. the conifers agathoxylon kumarpurensis (bajpai and singh) crisafulli and herbst nov.comb. and agathoxylon ningahense (maheshwari) crisafulli and herbst nov. comb. have been transferred from araucarioxylon; also podocarpoxylon indicum (bhardwaj) bose and maheshwari, chapmanoxylon jamuriense pant and singh and the new species chapmanoxylon oltaense crisafulli and herbst are described. chapmanoxylon preserves homogeneous pith, primary and secondary xylem; the other taxa only have secondary xylem all of which present interruptions in the growth and distorsion in transverse sections. these picnoxylic woods based on tracheidal characters are clasified in three groups: with araucarioid pits, with araucarioid-abietinoid pits and finally with araucarioid, mixed and tending to abietinoid pits. chapmanoxylon jamuriense, agathoxylon kumarpurensis and agathoxylon ningahense were found in the raniganj formation in india. the latter species was also recorded in the mount glossopteris (antarctica) and melo (uruguay) formations while agathoxylon kumarpurensis together with podocarpoxylon indicum were found in springfontain (south africa) , all from the permian. genus podocarpoxylon is also present in the triassic el tranquilo group (patagonia) and jurassic of rajmahal (india).