The Rosidae
Family Overview - The Myrtales
Onagraceae - the Evening Primrose Family
Diversity: Temperate
taxa are herbaceous - often perennial - with some woody taxa in the
tropics. A 'showy' family adapted to animal pollination (mostly insects
and hummingbirds) that includes many common Texas wildflowers ('buttercup'
- Oenothera
speciosa) - and a suite of ornamentals, including Fuchsia.
Distribution: Worldwide,
but mostly temperate and subtropical with considerable diversity in western
North America. We have 7 genera with 61 species in Texas, including
many common, conspicuous, elements of the local Spring flora.
Floral structure:
Significant features:
No 'handle' for this family with regard to vegetative structure, but the
flower is quite distinctive in that 1) all floral whorls are based
on a 4-merous structural pattern, 2)
the flowers are epigynous and, 3) the
hypanthium in many genera extends well
beyond the ovary .
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Oenothera speciosa
- a population or - more likely - a single plant since this
is a rhizomatous perennial species,
and a single flower (right) with yellow hypanthium
throat and four stigma lobes
reflecting 4-carpels (syncarpous)
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Oenothera speciosa
- side view of flower with hypanthium
intact (left) and opened (right). 'Strings' of pollen (right)
result from physical linkage of pollen grains in Oenothera
via hook-like structures on the pollen grain wall.
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Epilobium angustifolium - 'fireweed' of
the western U.S. is wind-dispersed via comose
seeds (frequent in the family) and therefore poised and ready
to take advantage of sunlight provided by forest fires:
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Population
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Inflorescence
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Flower
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Fuchsia species show reflexed sepals and epigyny
More information on the Onagraceae
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Notes, the Botany
201 homepage, or the Rosidae
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