Fig. 1.—Calamites. Part of transverse section of a young stem, showing pith, vascular bundles with secondary wood, and cortex. (× about 40.) From a photograph (Scott, “Studies”).

Fig. 4.—Palaeostachya pedunculata. Fertile shoot, bearing numerous cones and a few leaves. After Williamson (Scott, “Studies”).

Fig. 22.—Lyginodendron oldhamium. Transverse section of stem, showing the pith containing groups of sclerotic cells, the primary xylem-strands, secondary wood and phloem, pericycle and cortex. lt¹-lt⁵, leaf-traces, numbered according to the phyllotaxis, lt⁵ belonging to the lowest leaf of the five; ph, a group of primary phloem; pd, periderm, formed from pericycle. (× 3.)

Fig. 5.—Sphenophyllum insigne. Transverse section of stem, showing triangular primary wood, secondary wood, remains of phloem, and primary cortex. (× about 30.) From a photograph (Scott, “Studies”).