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.

Click images to enlarge and show more photo credit.

Key to Isolepis

Cyperaceae

Isolepis

Copy permalink to share

1 Spikelet scales with mucros or cusps 0.7-2.5 mm long; achenes ellipsoid, 0.6-0.8 mm long, 0.3-0.5 mm thick, about 2× as long as thick; [historic waif]; [subgenus Micranthae]
1 Spikelet scales acute, obtuse, or with a mucro to 0.2 (-0.5) mm long; achenes obovoid and usually trigonous, 0.7-1.6 mm long, 0.4-1.1 mm thick, 1-1.5× as long as thick; [collectively widespread].
  2 Achenes with 5-8 longitudinal ridges, cross-linked by many, finer transverse ridges, making a fine reticulum (use at least 10× magnification); scales of the spikelet not gibbous, not clasping the achene when shed; scales reddish to black; [historic waif, but also sometimes cultivated); [subgenus Isolepis, section Isolepis]
  2 Achenes finely to coarsely papillate (use at least 10× magnification); scales of the spikelet either gibbous (boat-shaped) tending to clasp the shed achene, or only slightly curved, and not clasping the shed achene; scales greenish, straw-colored, or slightly orange; [collectively widespread]; [subgenus Isolepis, section Cernuae].
    3 Achenes with all or at least 2 sides convex; scales of the spikelet not gibbous (boat-shaped), and not retaining (by clasping) the shed achene
    3 Achenes with all 3 sides planar to concave; scales of the spikelet gibbous, tending to retain (by clasping) the shed achene.
      4 Achenes (1.0-) 1.2-1.6 mm long; scales in middle of spikelet 1.8-2.0 mm long, with a short awn to 0.2 (-0.5) mm long
      4 Achenes 0.7-1.0 mm long; scales in middle of spikelet 1.0-1.2 mm long, mucronate < 0.1 mm