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Support the Flora of the Southeastern US

2024 has been a banner year for making the best flora we can imagine. We've created:
With financial support from people like you, we are aiming even higher in 2025. Together we can accomplish all this: Vote on our 2025 priorities
  • Add Global Conservation Ranks (GRanks) vote
  • Professional graphic keys (polyclaves) to individual families/genera vote
  • 2 new FloraQuest apps: Florida & Mid-South vote
  • Image overlays highlighting diagnostic characters with arrows vote
  • iNaturalist integration in FloraQuest vote
Write-in vote: vote
We've set a goal of recruiting 200 ongoing supporters to donate $15 or more each month in 2025. Please help us reach this goal and make next year's flora even better:
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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 Lythrum

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1 Flowers numerous in terminal spike-like thyrses; stamens usually 12; leaves opposite or whorled on the lower stem.
  2 Leaf bases cordate to rounded; stems puberulent
  2 Leaf bases cuneate; stems glabrous
1 Flowers solitary or paired in axils; stamens usually (4-) 6; leaves either opposite throughout, or opposite to subopposite below and alternate above.
    3 Leaves opposite throughout, mostly shorter than to about as long as the internodes, 1-6 mm wide
      4 Leaves elliptic, averaging ca. 2× as long as wide; stems decumbent to ascending
      4 Leaves linear, averaging 5-10× as long as wide; stems erect
    3 Leaves opposite or sub-opposite on the lower stem, alternate above.
        5 Annual; flowers present in nodes more-or-less throughout the plant; flowers homostylous, all alike, the stamens always included
        5 Perennial by basal stoloniferous outshoots; flowers present only at upper nodes; flowers heterostylous (either with an exserted style and included stamens, or vice versa)
          6 Floral tube 3-4 mm long; petals 2-3 mm long; calyx appendages about the same length as the calyx lobes; branch leaves abruptly and definitely reduced in size relative to the stem leaves, and widely spaced; [of sw. GA southward]
          6 Floral tube 5-6 mm long; petals 5-6 mm long; calyx appendages about 2× as long as the calyx lobes; branch leaves gradually reduced relative to the stem leaves, dense and overlapping; [collectively widespread in our area].
             7 Plants whitish-gray glaucous; leaves 3-8 mm wide
             7 Plants green or slightly glaucous; leaves 7-15 mm wide.
               8 Leaves ovate to lanceolate, widest at a point 1/6 to 1/2 of the way from the base to the apex, the base rounded to subcordate; stems mostly slender, to 8 dm tall; bracteoles mostly at the base of the pedicel
               8 Leaves lanceolate to linear-lanceolate, widest at a point 1/3 to 2/3 of the way from the base to the apex, the base cuneate, often narrowly so; stems stout, to 13 dm tall; bracteoles mostly on the upper pedicel, immediately below the floral tube