Monographs Details: Hypolytrum sylvaticum Poepp. & Kunth ex Kunth
Authority: Koyama, Tetsuo M. 1966. The systematic significance of leaf structure in the Cyperaceae-Mapanieae. Mem. New York Bot. Gard. 15: 136-159.
Description:Species Description - Leaf blades essentially inversely W-shaped, without median groove. Dermal tissues. Adaxial median surface consisting of tall, 3-layered translucent tissue, the component cells uniformly narrowly oblong (Fig. 4). Epidermal cells somewhat variable in height. Adaxial hypodermis 2- or in part 3-layered, interrupted by sclerenchyma above lateral costal vascular bundles, the component cells remarkably large, transversely oval or suborbicular. Abaxial hypodermis 1-layered, discontinuous at stomatal cavities; the component cells transversely oval, swollen. Mesophyll (Fig. 6) inconspicuously differentiated into palisade and spongy portions, with scattered transversely oblong tannin cells; palisade chlorenchyma (Fig. 6, pl) comparatively loose, scarcely 2-layered, the component cells round to transversely oblong; spongy chlorenchyma (Fig. 6, sp) with scattered intercellular spaces, the component cells transversely oblong, hardly lobed except abaxial ones. Vascular bundles arranged in a single row, distant, orbicular in outline; bundle sheath double, the inner bundle sheath complete, the component cells lignified but their walls not markedly thick, the outer bundle sheath of thin-walled translucent cells abaxially interrupted by sclerenchyma or complete in small vascular bundles. Frequently up to 5 metaxylem conducting cells outstanding. Sclerenchyma not extensively developed. Median vascular bundle supported by an abaxial deeply crescentiform girder (Fig. 4, s) and a small adaxial cap. Vascular bundles at both lateral costas supported by an adaxial low-T-shaped girder and an abaxial crescentiform girder (Fig. 5, a). Other large vascular bundles with an abaxial crescentiform girder; small vascular bundles without vascular scleren-chyma.
Note. Hypolytrum sylvaticum ssp. sylvaticum and H. nicaraguense, which are not described in this paper, showed precisely the same type of leaf blades in the transverse section. All these taxa are seemingly characterized by the more or less uniformly transversely oblong assimilatory cells and the inner sheaths of vascular bundles, which are little sclerified. In H. sylvaticum ssp. rubescens, the largest vascular bundles at both lateral costas have the bundle sheaths uniformly consisting of thin-walled, apparently little lignified mechanical cells only (Fig. 5). These bundle sheaths adaxially expand into a large translucent thickening (Fig. 5, t), which fills up the entire space between the metaxylem and the adaxial large T-girder.