Mapania macrophylla H.Pfeiff.

• Authority

  Koyama, Tetsuo M. 1966. The systematic significance of leaf structure in the Cyperaceae-Mapanieae. Mem. New York Bot. Gard. 15: 136-159.

• Family

  Cyperaceae

• Scientific Name

  Mapania macrophylla H.Pfeiff.

• Description

  Species Description - Leaf blades depressed-V-shaped with reflexed margins. Dermal tissues. Adaxial median surface grooved, the swollen translucent tissue consisting of irregularly oriented elliptic cells, roughly 3- or 4-layered (Fig. 30). Adaxial epidermal cells flat; abaxial epidermal cells taller than the adaxial ones, rectangular to almost square. Hypodermis absent. Mesophyll differentiated into chlorenchyma and translucent mesophyll, remotely divided by I-girders and associated vascular bundles. Translucent mesophyll (tm in figs.) of irregularly oriented large thin-walled cells, without conspicuous inter-cellular spaces. Chlorenchyma extremely scanty; palisade chlorenchyma (pl in figs.) 2- or 3-layered, with scattered small fiber strands; assimilatory cells rather irregularly oriented, comparatively loose, longitudinally oblong to broadly oval; spongy chlorenchyma (sp in figs.) with scattered small intercellular spaces; assimilatory cells transversely oblong or linear, some conspicuously lobed. Ground tissue of the median costal region entirely consisting of round translucent cells. Vascular bundles arranged in adaxial and abaxial transverse rows, 3 or 4 adaxial small vascular bundles present between 2 large abaxial bundles (Fig. 29), each oval or elliptic in outline. Bundle sheaths double, the inner sheath of sclerified cells complete, the outer sheath of thin-walled translucent cells discontinuous adaxially or at both ends. Two metaxylem conducting cells markedly large; phloem proportionately rich. Sclerenchyma poorly developed. Adaxial small vascular bundles with an adaxial low-I-shaped girder, consisting of 2 or 3 longitudinal rows of fiber cells (Fig. 32). Abaxial vascular bundles supported by an abaxial crescentiform girder and an adaxial tall I-girder, the adaxial girder traversing translucent mesophyll consisting of round ligneous cells, accompanied by translucent cells (Fig. 28, t). Vascular bundle at median costa completely surrounded by sclerenchyma (Fig. 30).

• Discussion

  Note. The tall I-girders dividing the mesophyll involve two different sclerified cells. The adaxial portion, which is embedded in the chlorenchyma, consists of fiber cells polygonal in outline, while in the other portion the component cells tend to be round in cross section with slightly thinner cell walls. Such differentiation in sclerenchymatous cells was also noticed in the tall I-girders of Diplasia karataefolia.