Bucklandia Sahnii sp. nov. from the Jurassic of the Rajmahal Hills, Bihar

Abstract

The description of this new species of Bucklandia is based on specimens from Amarjola, Amrapara, Rajmahal Hills, India. The stem is covered with persistent leaf-bases which are very variable in shape and size. Pith wide, surrounded by a broad zone of xylem, phloem and bark. The importance of this stem lies mainly on the secondary wood which is compact with sharply marked growth rings. Medullary rays are very conspicuous by their number and crowded occurrence. Most of the rays are uniseriate, but biseriate ones also occur frequently. The tracheids of the early wood have mainly scalariform pitting. The early wood shows various types of pitting, varying from scalariform to multiseriate. Pits seen on the radial walls of the rays are bordered. The number of bordered pits in a cross-field varies from 1 to 6 or more. Primary xylem is endarch. B. Sahnii differs from B. indica in having tracheids with scalariform as well as multiseriate bordered pits; no scalariform pitting was observed in B. indica. Comparisons have been made with the fossil Cycadeoidean stems and Homoxylon rajmahalense. The secondary wood of B. Sahnii has been found to be very similar to that of H. rajmahalense and now H. rajmahalense has been said to be a Bennettitalean wood.