Abstract
Cell walls of scarious floral leaf cells in seven plant species were observed under a transmission electron microscope (TEM), a scanning electron microscope (SEM) and a polarization microscope. Generally, floral leaves are composed of parenchyma cells with only primary cell walls. However, it was clarified that there were secondary cell walls showing orientation of cellulose microfibrils for all cells of scarious floral leaves in the seven plant species investigated. The fine structures of secondary cell walls varied as follows: Helichrysum bracteatum L., Acroclinium roseum L., Rhodanthe manglesi L. and Xeranthemum annuum L. in the Compositae family formed a reticulate or striped structure similar in morphology to secondary thickening of tracheary elements or transfer cells. Gomphrena globosa L. and Gomphrena haageana L. in the Amaranthaceae family formed a layered structure similar to fiber. Limonium sinuatum L. in the Plumbaginaceae family formed a folded structure similar to the sclereid of seed coat.
