Fig. 7

Comparative leaf morphology and anatomy of Ephedra in this study. A–D Overview of E. tweediana leaf morphology under a stereomicroscope. A, B Stem apex showing leaves from the first and second nodes in frontal and lateral views, respectively. C, D Detail of the fifth node from the stem apex showing developing leaves in frontal and lateral views, respectively. Note the development of the lateral, papyraceous zone. E–G E. tweediana (male individual). E Toluidine blue O and PAS staining. Mucilage cells (*) are present throughout the mesophyll, cellulosic fibers (arrows) are associated with vascular bundles, and stomata are present on both leaf surfaces (arrowheads). F Polarized light microscopy of section in E showing the birefringence and distribution of cellulosic fibers (arrows). G Positive PAS staining of mucilage in mesophyll cells. H–J E. tweediana (female individual). H General overview, arrows indicate vascular bundles, two axillary buds (b) are visible and mucilage cells (*) are distributed throughout the mesophyll. I High magnification of the vascular bundle in D, showing cellulosic fibers (arrows) associated with the bundle and also distributed throughout the mesophyll. J Polarized light microscopy of section in I showing the birefringence of xylem cells (x) and cellulosic fibers (arrows). K E. triandra (male individual), with a different pattern from that found in E. tweediana: cellulosic fibers (arrows) are associated with vascular bundles, and also present in bundles abaxially and in layers adaxially. Mucilage cells are found in multiple layers on the abaxial surface. L Polarized light microscopy of section in K showing the distribution and birefringence of the cellulosic fibers. M E. multiflora (female individual) with tannin cells (t) in the adaxial epidermis and also distributed in one or two layers on the abaxial face. Cellulosic fibers (arrows) differentiate in several adaxial layers in the mesophyll. L Polarized light microscopy of section in K showing the distribution and birefringence of the cellulosic fibers. Node 1 (n1), node 2 (n2), node 4 (n4). Scale bars: 1 mm (A–D), 100 µm (E, F, K–N); 50 µm (G, I, J); 200 µm (H)