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Nuphar

See list of 3 species in this genus

The flowers of Nuphar are interesting. The outer whorl of perianth is composed of 5 or 6 petaloid sepals. The inner whorl of perianth is represented by many small, thick structures that are transitional in appearance to the stamens. Beal (1956) placed all our species as infraspecific taxa under Nuphar lutea, a European plant. Subsequent studies have shown that our species are distinct from N. lutea. However, further research is needed to determine the correct placement of N. microphylla, which appears to be closely related to the Eurasian N. pumila (Timm) DC. (and was synonymized under the latter name by Beal). References: Wiersema and Hellquist (1997), Hellquist and Crow (1984).

  • 1a. Sepals 1–2.5 cm long, numbering 5 per flower; anthers predominantly shorter than the filaments, 1–3 mm long; fruit strongly constricted below the red stigmatic disk; petals and stamens promptly deciduous, usually not persisting as remnants at the base of the fruit; basal sinus of leaf blade (42–) 54–90% of the length of the blade midrib [Fig. 54]
  • 1b. Sepals 2.5–5 cm long, numbering 6 per flower; anthers longer than the filaments, 3–9 mm long; fruit only slightly constricted below the green (rarely red) stigmatic disk; petals and stamens tardily deciduous, usually persisting as remnants around the base of the fruit; basal sinus of leaf blade 30–59 (–62)% of the length of the blade midrib [Fig. 55]
    • 2a. Petioles strongly flattened on the adaxial surface, often wing-margined; leaves with a narrow, closed, basal sinus, floating; sepals red at the base of the abaxial surface; fruit often purple
    • 2b. Petioles terete to oval in cross-section, not wing-margined; leaves with a broad, open, basal sinus, often emergent; sepals green (rarely red) at the base of the abaxial surface; fruit green

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