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; global diversity of ca. 640 species in ca. 20 genera. We have 7 genera with 72 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. |  |
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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Fuchsia species show reflexed sepals and
epigyny
More information on the Onagraceae