Contemporary Circumscription Compared with A Utah Flora 4th ed.
Bio430
Onagraceae
No differences at the family level; a 2007 revision based on years of careful study has changed generic circumscriptions considerably.
Key Features
Primarily four merous flowers with inferior ovaries (4 carpels), an often markedly elongate hypanthium, and sepals often reflexed. Stamens are equal or twice the number of petals, and pollen may ‘string together’ by viscin threads.
Gayophytum; flowers are ~ 5 mm across
Gayophytum
Taraxia breviflora - this species prefers moist sites, such as this lowland adjacent to a reservoir in Oregon
Taraxia breviflora - stigma is globose rather than 4 lobed.
Chylismia claviformis
Chylismia claviformis
Chylismia claviformis
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Oenothera
Oenothera - pollen grains form chains by adhering to each other via vicin threads
Oenothera villosa
Oenothera villosa
Oenothera villosa
Oenothera villosa - with hypanthium purposefully partially split to show style is free within this elongated floral cup
Oenothera villosa - section through 4 carpellate inferior ovary
Epilobium (Zauschneria) garrettii
Epilobium (Zauschneria) garrettii - section trhough hypanthium showing style free to base of hypanthium/apex of inferior ovary
Epilobium (Zauschneria) fruit dehiscing with four valves; Epilobium seeds bear a tuft of hairs
Clarkia
Clarkia
Clarkia pulchella; sepals in Onagraceae are either erect, reflexed, or they fold to one side because their tips don't completely separate
Epilobium campestre -- small flowers with notched petals
Epilobium angustifolium
Epilobium angustifolium
Chylisma scapoidea
Chylisma scapoidea; thick inferior ovary apparent between reflexed sepals and narrower pedicel at base; a short hypanthium is hidden underneath the sepals
Chylisma scapoidea; flowers in buds show that the hypanthium is short in this species
Chylisma scapoidea; 8 stamens, 4 are longer than the other 4
Camissoniopsis hirtella; this species epithet refers to its hairs
Fuchia sp.; these flowers may dangle for pollination. Note the small round inferior ovary and elongate, funnel shaped hypanthium
Fuchia sp. sectioned through hypanthium. The rim of the hypanthium where the free petals, sepals, and stamens are attached is evident
Fuchia sp.; section through 4-carpelate ovary
Oenothera curtiflora (= Gaura parviflora); this species 4+ feet tall along rural and farm roadsides in moist areas in Utah valley (and elsewhere). Its fruit is indehiscent (nutlet).
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