binervate

1. (zoology, botany) Of leaves, wings, etc. having only two nerves or ribs.Examples: "The binervate wings of this species are elongated and nearly transparent."; "(Hookeria laete-virens): stem procumbent, subpinnate; leaves suddenly acuminate, ovate, or ovate-oblong, with a thickened margin, sharply toothed, binervate."; "(Pilotrichella welwitschii): ...the ramuline leaves are spathulate from a contracted base, obsoletely binervate, more longly acuminate, with upper margins involute and serrulate. (Erythrodontium bicolor): Ramuline leaves, appressed when dry, erecto-patent when wet, 0.85 mm. long by 0.375 mm. wide, from a broad cordate base elliptic-ovate acuminate, slightly hollowed, shortly binervate, with margins erect or slightly recurved, minutely serrulate above middle..."not-comparable