待宵草(月見草)屬

HOCH, PETER C. and WAGNER, WARREN L.

Oenothera stricta Credit: HAST

Annual, biennial or perennial herbs, from a taproot or clumped and spreading by rhizomes or lateral roots. Leaves alternate, often in a basal rosette, entire, toothed, or pinnately lobed; stipules absent. Flowers actinomorphic, 4-merous, in axils of upper reduced leaves, usually opening near sunset; sepals 4, reflexed in flower; petals 4, yellow, white or rose-purple, tip often notched; stamens 8; pollen shed singly; ovary 4-locular; stigma deeply 4-lobed. Fruit a many-seeded capsule, usually dehiscent, straight or curved, terete to 4-ribbed or winged, +/- sessile. Seeds in 2 (1 or 3, not in Taiwan) rows per locule or clustered.

A genus of about 120 species native to temperate or subtropical N and S America but some species widely naturalized; five species occur in Taiwan. Several species in Taiwan have the feature of permanent translocation heterozygosity, characterized by self-pollination, about 50% pollen fertility (note: sterile pollen is smaller than fertile and thus can be assessed with a hand lens), and the formation of a ring of 14 chromosomes at meiotic metaphase I.

• Dietrich, W. & W.L. Wagner. 1988. Systematics of Oenothera section Oenothera subsection Raimannia and subsection Nutantigemma (Onagraceae). Syst. Bot. Monogr. 24: 1-91.
• Munz, P.A. 1965. Onagraceae. N. Amer. Fl. II, 5: 1-278.
• Peng, C. I & S. Huang. 1986. Oenothera laciniata Hill (Onagraceae), a previously unrecorded species in Taiwan. Bot. Bull. Acad. Sin. 27: 45-51.
  
  

  KEY TO SPECIES
  1 Petals white, fading purple; seeds in clusters in each locule;fruit club-shaped, 4-winged.   Oenothera tetraptera + Petals yellow, fading pale yellow to orange or red; seeds in 2 rows in each locule; fruit lanceolate or cylindrical, sometimes slightly wider toward apex, not winged.   (2)         2 (1) Fruit lanceolate; erect biennial; flowers numerous in generally dense spikes; seeds angled, irregularly pitted.   (3) + Fruit cylindrical; usually decumbent or weakly erect annual or perennial (O. stricta sometimes a biennial); flowers few in upper axils; seeds ellipsoidal, not angled.   (4)         3 (2) Leaves distinctly crinkled, at least toward the base; seeds c. 50% abortive; sepals usually reddish, 28-45 mm long; petals 35-50 mm long; anthers 10-12 mm long.   Oenothera glazioviana + Leaves flat, not crinkled; seeds c. 100% fertile; sepals green, rarely reddish, 12-20(-28) mm long; petals 10-25 (-30) mm long; anthers 3-6(-9) mm long.   Oenothera biennis         4 (2) Fruit wider toward apex; floral tube straight in young buds; petals 15-25(-30) mm long, generally with a red spot at base; sepals 14-20 mm long.   Oenothera stricta + Fruit the same diameter throughout or tapering toward apex; floral tube curved upward in young buds; petals 5-13(-20) mm long, without a red spot at base; sepals 5-15 mm long.   Oenothera laciniata

  Lower Taxa
  

  • Oenothera biennis L.
  • Oenothera glazioviana Micheli
  • Oenothera laciniata J. Hill
  • Oenothera stricta Ledeb. ex Link
  • Oenothera tetraptera Cav.

  Related Synonym(s):
  

  • Oenothera erythrosepala Borbas = Oenothera glazioviana Micheli
  
  

   

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