FIGURE 2. Typical and atypical roots. A in Plant structure ontology: How should we label plant structures with doubtful or mixed identities? *

FIGURE 2. Typical and atypical roots. A. Cylindrical root of Asplenium sandersonii (Aspleniaceae) showing prominent root cap and more proximal zone with root-hairs. Scale bar = 250 µm. B–C. Longitudinal sections of Pinguicula root-tips (Lentibulariaceae). B. Pinguicula vulgaris with root-cap. Scale bar = 200 µm. C. Pinguicula moranensis lacking rootcap. Scale bar = 200 µm. D–F. Ribbon-like root of Podostemum distichum (Podostemaceae). D. Cross-section of ribbonlike root. Scale bar = 400 µm. E, F. Two views of root-tip with asymmetrical root cap, shown from slightly above and slightly below. Scale bars = 500 µm. G–H. Ribbon-like root of Ledermanniella spp. (Podostemaceae). G. Ledermanniella bosii (microtome, transversal section) showing adhesive hairs ("root-hairs") along ventral side. Scale bar = 250 µm. H. Ledermanniella bowlingii. Ribbon-like root shown from ventral side, with exogenous lobe and root-tip lacking cap. Scale bar = 2 mm.