FIGURE 2. Gracilaria cearensis. A in Taxonomic reassessment of Gracilaria cearensis (Rhodophyta, Gracilariales), a poorly defined yet common flattened species based on morphological and molecular analysis including topotype collections

FIGURE 2. Gracilaria cearensis. A. Transverse section close to base of main axis, showing various layers of cortical cells and medullary cells with thickened walls. B. Transverse section close to apex, showing abrupt transition between cortex and medulla. C. Transverse section showing gradual transition between cortex and medulla. Note medulla composed of thick-walled cells. D. Detail of cortical region, composed of 1–2 cortical cell layers. Note the gradual transition between cortex and medulla. E. Surface view of tetrasporic blade. F. Transverse section of tetrasporophyte cortex, showing cruciate tetrasporangia. G. Surface view of a male thallus with scattered spermatangia. H. Transverse section of spermatangial thallus, showing shallow textorii-type conceptacles. I. Longitudinal section of a cystocarp. J. Longitudinal section of cystocarp, showing tubular nutritive cells (arrows). K. Detail showing the central fusion cell (f). L. Tubular nutritive cells connecting gonimoblasts to pericarp (arrows). Note small cortical cells in cystocarp floor (arrowhead). Scale bars: A–C, I, J = 100 μm, D–H, K, L = 25 μm.