Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.

Key to Dioscorea

Dioscoreaceae

Dioscorea

Copy permalink to share

1 Leaves with a slightly to strongly concave section at the transition from the basal lobes to the terminal portion of the leaf; leaves alternate, opposite, or a mixture of alternate and opposite.
  2 Leaf apex mucronate or acuminate; leaf lateral lobe apices rounded; petiole base not clasping; leaves 3-9 cm wide
  2 Leaf apex caudate; leaf lateral lobe apices acuminate; petiole base clasping; leaves 7-42 cm wide
1 Leaves with continuously convex lateral margins (except just below the acute to acuminate leaf apex) or with slight undulations of straight to very slightly concave sections.
    3 Aerial tubers never present; perennial from rhizomes < 1.5 cm in diameter; leaves whorled, alternate, or a mixture of whorled and alternate; [native species, usually of forests and woodlands]; [section Macropoda].
      4 Leaves with 7 main veins; staminate inflorescences usually of 1 large and 1-2 smaller secondary panicles in each axil (of upper stem leaves); filaments inwardly curved, ca. 0.4 mm long; anther lobes connate; tepals oblong; leaf margins often with subtle, very broad lobes, the margin thus with straight or very slightly concave segments; [of SC south]
      4 Leaves with 9 or more main veins; staminate inflorescence a single panicle in each axil (of median or upper leaves); filaments straight, ca. 0.2 mm long; anther lobes separate; tepals ovate; leaf margins convex; [widespread in our area]
    3 Aerial tubers present; perennial from large, vertically-oriented tubers; leaves alternate, or a mixture of alternate and opposite; [non-native species, usually in disturbed areas, especially in bottomlands]; [section Enantiophyllum].
        5 Stems with 2-4 wings or angles (these often purplish); leaves alternate below, opposite and decussate above; aerial tubers dark-brown and elongate; stem twining from left to right (dextrorse; looking from below, the stem turns clockwise)
        5 Stems terete; leaves alternate; aerial tubers tan to light brown, usually globose; stem twining from right to left (sinistrorse; looking from below, the stem turns counterclockwise)