Onagraceae 01 Floral formula 01-Floral formula Floral formula for the Onagraceae. Note that this is a 4-merous flower and that a hypanthium is present. The ovary is inferior. Onagraceae 02 Introduction 02-Introduction The Onagraceae is found throughout much of the world; the family is most diverse in the southwestern United States and Mexico. A number of species occur in wetlands or are aquatic.

There are 16 to 24 genera and about 650 species. Onagraceae 03 Fuchsia habit 03-Fuchsia habit Most members of the Onagraceae are herbaceous, although some can be shrubs, as is this species of Fuchsia. Photo by K. R. Robertson in the Jardim Botanico da Madeira, Funchal. The island if Madeira is about 300 west of the African coast and is politically part of Portugal. Onagraceae 04 Fuchsia flower 04-Fuchsia flower Flower of a cultivated Fuchsia, which typically hangs upside down (and is pollinated by hummingbirds). Note the inferior ovary (yellow arrow). Photo by K. R. Robertson of a plant cultivated in Cambridge, Massachusetts. Onagraceae 05 Fuchsia flower in longitudinal section 05-Fuchsia flower l.s Longitudinal flower of a flower of Fuchsia. Note the inferior ovary and the hypanthium.

The inset closeup of the ovary in longitudinal section shows the axile placentation. Photo by K. R. Robertson and D. L. Nickrent from plants cultivated at the University of Illinois. Onagraceae 06 Oenothera flower 06-Oenothera flower Close-up of the top of a flower of Oenothera. The flowers are 4-merous. Note that the style comes from the opening of the hypanthium. Photo by K. R. Robertson and D. L. Nickrent from plants cultivated at the University of Illinois. Onagraceae 07 Oenothera flower in partial longitudinal section 07-Oenothera flower l.s Longitudinal section through the top half of a flower of Oenothera. Note the hypanthium. Photo by K. R. Robertson and D. L. Nickrent from plants cultivated at the University of Illinois. Onagraceae 08 Oenothera ovary 08-Oenothera ovary Longitudinal and cross sections through the ovary of a flower of Oenothera. Note the inferior ovary, the axile placentation, and the extremely numerous ovules. Photo by K. R. Robertson and D. L. Nickrent from plants cultivated at the University of Illinois. Onagraceae 09 Oenothera anthers and viscin threads 09-Oenothera anthers Anthers of Oenothera. Note that in the genus Oenothera (but not the whole family), viscin threads stretch between pollen grains. Photo by K. R. Robertson and D. L. Nickrent from plants cultivated at the University of Illinois. Onagraceae 10 Oenothera missouriensis, Missouri primrose 10-Oenothera miss. habit The Missouri evening primrose (Oenothera missouriensis) has a hypanthium and style that is 6 inches or more long. This species is native to prairie-like areas called glades in Missouri; it is sometimes cultivated in gardens. Photo by K. R. Robertson from plants in cultivation at the Case Estates, Arnold Arboretum of Harvard University. Onagraceae 11 Oenothera missouriensis flower 11-Oenothera miss. flower The flowers of Oenothera missouriensis are 3–4 inches across. They are fragrant, open in the evening, and are pollinated by night-flying sphinx moths. Photo by K. R. Robertson from plants in cultivation at the Case Estates, Arnold Arboretum of Harvard University. Onagraceae 12 Clarkia 12-Clarkia The genus Clarkia has more than 30 species ranging from western North America to northern South America. The genus is named for William Clark (1770-1838), the co-leader of the Lewis and Clark expedition. Photo by K. R. Robertson from plants cultivated at the University of Illinois. Onagraceae 13 Epilobium habit 13-Epilobium habit Epilobium angustifolium, fireweed or willow-herb, often occurs on recently cleared woodlands and burned areas in northern latitudes all across North America and Eurasia. Photo by K. R. Robertson near Loch Tay, Scotland. Onagraceae 14 Epilobium inflorescence 14-Epilobium inflorescence The raceme inflorescences of Epilobium angustifolium can be a foot or more long. Photo by K. R. Robertson on Mt. Washington, New Hampshire.