Figure 2.

A, Simplified phylogenetic tree showing the minimum stratigraphic ranges of selected groups based on fossils (thick bars) and their minimum implied range extensions (thin lines). Extinct and living plant groups are shown. Adapted from Kenrick and Crane (1997b). B, Early rooting system in Zosterophyllum shengfengense from the Lower Devonian of Qujing City, Yunnan Province, south China. The plant shows a tufted habit of numerous aerial axes, which are supported by a rhizome and shallow rooting system. C, Reconstruction of Z. shengfengense (photograph in B and reconstruction in C courtesy of Hao Shougang). Car, Carboniferous; Dev, Devonian; L, lower; M, middle; Mis, Mississippian; Ord, Ordovician; Pen, Pennsylvanian; Sil, Silurian; U, upper. Bars = 10 mm in B and 20 mm in C.