Oenothera macrocarpa (syn. Oenothera missouriensis), the bigfruit evening primrose, Ozark sundrop or Missouri evening primrose, is a species of flowering plant in the evening primrose family Onagraceae, native to Mexico and the south-central United States, where it is found in calcareous prairies and limestone outcrops.
This herbaceous perennial produces a red stem 6-12 in. (15-30 cm) in height. The large (3 inch) wide flowers are cup shaped, canary yellow and have a mild fragrance. They are produced in great numbers from early to mid summer. Leaves are dark green and lanceolate, and bunched along the trailing stem. The seed pods are 4-winged and 2 to 3 inch long.
The seed pods are often used in flower arrangements. This plant is also grown in gardens for its flowers. It is suitable as a groundcover in poor, stony soil which does not become waterlogged in winter, in full sun. It has gained the Royal Horticultural Society’s Award of Garden Merit.
There are five commonly accepted varieties. These are:
- O. macrocarpa var. fremontii - restricted to Kansas and southern Nebraska
- O. macrocarpa var. incana - southern Kansas, western Oklahoma and northern Texas
- O. macrocarpa var. macrocarpa - the most widespread; Texas to the Ozark Mountains, with disjunct populations in Tennessee's Nashville Basin
- O. macrocarpa var. mexicana - known only from Coahuila, Mexico
- O. macrocarpa var. oklahomensis - southern Kansas, Oklahoma and northern Texas
- "Oenothera macrocarpa". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 29 January 2016.
- Shinners and Mahler's Illustrated Flora of North Central Texas Online
- Missouri Botanical Garden
- "Perennial Resource: Oenothera missouriensis". Archived from the original on 2012-03-17. Retrieved 2011-03-15.
- "RHS Plantfinder - Oenothera macrocarpa". Retrieved 14 April 2018.
- "AGM Plants - Ornamental" (PDF). Royal Horticultural Society. July 2017. p. 69. Retrieved 14 April 2018.
- "Oenothera macrocarpa". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 18 January 2017.
- Chester, Edward (2015). Guide to the Vascular Plants of Tennessee.
- Wagner, Warren; Hoch, Peter; Raven, Peter (2007). "Revised Classification of the Onagraceae". Systematic Botany Monographs. 83. JSTOR i25027967.