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See list of 4 genera in this family
  • 1a. Plants aquatic, without aerial stems, forming colonies by slender stolons in submersed populations (annuals in emersed plants); flowers 1–3 mm wide; androecium with 2 stamens; leaf blades narrower than 2 mm
  • 1b. Plants terrestrial or aquatic, with aerial stems, not colonial (forming terrestrial colonies by creeping stems in Mazus miquelii); flowers wider than 3 mm; androecium with 4 stamens; leaf blades much wider than 2 mm
    • 2a. Inflorescence a spike-like raceme, the pedicels very short [Fig. 764]; fruit an achene
    • 2b. Inflorescence a raceme or of solitary flowers from the axils of foliage leaves, in either case borne on evident pedicels [Fig. 763]; fruit a capsule
      • 3a. Bracts subtending the flowers alternate; basal, connate portion of the calyx not ribbed or winged, much shorter than the lobes
      • 3b. Bracts subtending the flowers opposite [Fig. 763]; basal, connate portion of the calyx 5-ribbed (the ribs sometimes wing-angled), longer than the lobes

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 Show photos of:   Each photo represents one genus in this family.