B. Papp szerk.: Studia Botanica Hungarica 36. 2005 (Budapest, 2005)

Bercu, R.: Contributions to the anatomy of Asplenium ruta-muraria

Transections of the petiole and rachis cut from the base up to 1.5 cm disclose almost the same succession of tissues, that is a unistratose epidermis covered by cuticle, a cortex and a stele. Below the epidermis there is the hypodermis, consisting of a few layers of compactly arranged sclerenchyma cells. The hypodermis is internally followed by a region of ground tissue (Fig. 3B). Remarkable is the abundance of starch grains in the cortex and the presence of a single packet of sclerenchymatous cells (Figs 3A, B). The sclerenchyma packet of cells from 2 cm up to the tip of the base is absent (Figs 5-7). The stele is monofascicular, composed of two centrally located metaxylem strings. The phloem surrounds the xylem elements. That attributes to the vascular bundle a hadrocentric structure (Fig. 3C). The two xylem curved strings configuration reveals that initially two vascular bundles from the rhizome join together to form a foliar trace (Figs 2A, 3C). Fig. 3. Cross section oflhe petiole base. - A: General view (xl 15). - B: Portion of the epidermis and cortex. - C: The stele (x 150): C = cortex, E = epidermis, H = hypodermis, IC = inner cortex, Ph = phloem, Mx = metaxylem, Pc = pericycle, Px = protoxylem Scl = sclerenchyma, St = stele, SG = starch grains, SS = starch sheath. Orig.