A Contribution to our Knowledge of the Vascular System of the Genus Equisetum

Kate Barratt
1920 Annals of Botany  
I N spite of the large amount of work already published on the subject of the anatomy of Equisetum, of which an excellent chronological account has been given by Lady Isabel Browne (1), there still seems to be a considerable lack of agreement as to the nature and origin of the various parts of the vascular system. The presence or absence of centripetal wood is one of the most prominent of these questions. As a contribution towards the solution of some of these problems it was decided to
more » ... e a more thorough investigation of the anatomy of the sporeling, and to bring together and amplify our information on the development of the vascular system. Hofmeister (3) , as long ago as 185z, included a brief reference to this subject in his account of the genus. He gave an excellent figure of a young sporeling at the stage when its first lateral shoot was developing, but. he does not refer in detail to the nature of the vascular structure. In 1899 Jeffrey (4) described the development of sporelings of Equisctum hicmale and E.limosum, but only dealt generally with the anatomy of the young plant. It was hoped that a further investigation of the sporeling anatomy would throw ligQt upon the following points : 1. The nature of the stelar anatomy of the primary axis. z. The phylogeny of the internodal bundle, with special reference to the metaxylem. 3· The elucidation of the vascular system of the node, in relation to the internode and the question of secondary thickening. METHODS. One of the reasons for the incompleteness of our knowledge of these plants in their young stages probably lies in the fact that the sporelings are very slender and fragile, and that previous investigations have been largely confined to the examination of microtome sections. Although serial sections have been used in this investigation, another
doi:10.1093/aob/os-34.2.201 fatcat:4t7ixd35nnanxhyhkriq7obqfe