The genus Sphenophyllum was originally established for leaf compressions but is now also used for permineralised axes. In crsoss section the axes show a typical triarch xylem with secondary growth. Sphenophylls were herbaceous plants, at least several species had a scrambling growth habit. The various Sphenophyllum foliage species are valuable index fossils for the Upper Carboniferous and Lower Permian. Online Image Coll.
All species are herbaceous.
The following site gives some information on extant sphenophytes. Modern sphenophytes Univ. The last check of the list of links was done on 25 November 2000. Ratings are of course subjective but should be helpful for finding the fastest way to good pictures on the web. Own pictures are of course not rated.