Diplasia karataefolia Rich.

• 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

  Diplasia karataefolia Rich.

• Description

  Species Description - Leaf blades depressed- V - shaped with reflexed margins and a shallow adaxial median groove. Adaxial surface. Swollen translucent tissue at the median groove 4-layered; epidermal cells transversely oblong; hypodermal cells square to oblong or longitudinally rectangular; a few fiber cells scattered toward margins of the median groove. Epidermis uniformly consisting of flat cells. Hypodermis almost entirely sclerified. Mesophyll differentiated into palisade chlorenchyma (pl in figs.), spongy chlorenchyma (sp in figs.) and translucent mesophyll (tm in figs.), separated by mechanical tissues and vascular bundles. Translucent tissue occupying most part of mesophyll, the component cells thin-walled, varying in shape and size, much larger than assimilatory cells. Chlorenchyma extremely scanty; palisade chlorenchyma as a rule 3-layered, the adaxial layer with longitudinally oblong cells, compact, the middle layer with round cells, the abaxial layer with transversely oblong cells, more or less decurrent to adaxial portion of mechanical tissues; spongy chlorenchyma 2- or 3-layered, with scattered small fiber strands, the component cells transversely oblong. Vascular bundles. One to 3 (mostly 2) vascular bundles of large, medium and small size longitudinally arranged in association with girders, elliptic or orbicular-oval in outline. Bundle sheaths double; inner sheath consisting of thick-walled ligneous cells complete; outer sheath of thin-walled translucent cells interrupted adaxially or abaxially by vascular sclerenchyma, or occasionally complete in middle vascular bundle in a group of 3. Sclerenchyma. Adaxial and abaxial vascular bundles supported by a girder of respective side; girders tall or low, mostly I-shaped, accompanied by usually 1-layered translucent sheath (t in figs.), a few abaxial low girders tending to be turbiniform. Unicellular layer of sclerenchyma replacing most part of hypodermis of adaxial surface.

• Discussion

  Note. The translucent cells adjoining the I-girders differ from the translucent and assimilatory cells of the mesophyll by thicker cell walls, and are thus considered to belong to the supporting tissue rather than to the ground tissue. The vascular bundles in longitudinal rows are connected by mechanical translucent cells of the same type. The structure described above recalls that of Lagenocarpus rigidus reported by Koyama (1965) especially in the arrangement of vascular bundles and the well developed I-girders.