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Herbal Botany - Evening Primrose

This is a test run for an Herbal Botany blog series Tito and I want to do together. Each entry will focus on one plant family. The ability to recognize plant families is essential to identifying specific plants used as medicine. Knowing the plant family of an individual significantly narrows down the list of possible species. This also saves a lot of time when using dichotomous keys like the Jepson Manual or Plants of the San Francisco Bay Region, which are organized by plant families.

Today we focus on the Onagraceae (Fushia/Evening Primrose) family. It is widespread throughout California accounting for many gorgeous ornamentals, and wildflowers notably Clarkias, Oenotheras, Camissonias and Ludwigias (Beildleman, 2014, p.232). Although some cultivated varieties may be woody, ie. Fuschias, the vast majority of our California native plants are herbaceous - woodless annuals or perennials (Beildleman). The leaves are variable in that they can be either alternate, opposite, or whorled, but are usually simple (not compound like a fern or buckeye) with toothed margins (TJM2). The flowers are generally radially symmetrical, and bisexual (having both female and male parts on the same flower) (Simpson, 2010, p.357). One of the most important characters we use to recognize this family is the presence of a hypanthium (floral cup) - a region of the flower where the sepals, petal, and stamens are fused into one structure. The hypanthium is connected to an inferior ovary, often elongated and frequently differing in color (TJM2). One can recognize a hypanthium by cutting into the structure between the sepals and ovary, and confirming that the sepals, petals, and stamens all emerge at the same level. As described in Jepson, most California specimen have 4 sepals, 4 petals, 4 or 8 stamen (male parts), 4 carpels (female parts). The number of carpels can sometimes be easily counted in this family when the stigmas are lobbed like a plus sign, but the stigmas are also often rounded like a Frisbee in which case counting the number of carpels is more complicated, yet rarely necessary. You can memorize the number of floral parts listed above by using the floral formula 4-4-8-4, in the order sepals, petals, stamens, carpels. We use 8 as the number of stamen as it it most common in the family.

Camissonia claviformis - Brown Eyed Primrose

One of our medicinal members of this family is the Evening Primrose including Oenothera elata ssp. hookeri, O. biennis, O. californica, O. pallida, O. villosa, as listed by Michael Moore in Medicinal Plants of the Mountain West. The whole plant is edible as cooked greens, boiled roots, or seeds. The herb is diuretic, anti-spasmodic, anti-inflammatory and may act as a sedative nervine. It also has affinities to the respiratory system, lower bowels, generative organs (reproductive), and skin (integumentary). It is commonly used for hormonal regulation and menstrual cramping and pain. The seeds in particular contain 20% linoleic acid and gamma-linoleic acid (Moore p.113) giving it anti-inflammatory properties as well as potential to regulate hormones and hypersensitivities. Evening Primrose Oil is often touted as a remedy to Asthma and Eczema, however, I have also seen it make symptoms worsen. Some studies show it to be useful, some ineffective, and others inconclusive, therefore, it may be dose dependent and relative to physiological constitution or other factors in individual people. See for example Bamford et all 2013; Chung et all 2013; Schlichte et all 2016.

Cynthia Athina Kemp Scherer, in Alchemy of the Desert, describes using White Evening Primrose (Oenothera deltoides) Flower Essence in clearing a vision of our soul purpose. As a night blooming plant, it is useful in helping us move through dark times to awaken to our true selves (p. 308). This is powerful medicine for these dark times, giving us support to heal our past so that we can show up in our power.

Please give me feedback using the comment section below if you want to see more blog entries like this one. Was this too basic, too advanced? Is there anything I need to clarify? Is there a particular family you would like to learn about next? Looking forward to creating more Herbal Botany blog post soon.

**This information is for educational purposes only and is not intended as a substitute for medical care. Please consult your health care practitioner or work with a trained herbalist.


Baldwin, B. G., Goldman, D. H., & Vorobik, L. A. (2012). The Jepson manual: Vascular plants of California. Berkeley, Calif: University of California Press.

Bamford, J. T., Ray, S., Musekiwa, A., Van, C., Humphreys, R., & Ernst, E. (2013, April 30). Oral evening primrose oil and borage oil for eczema. Retrieved from

Beidleman, L. H., & Kozloff, E. N. (2014). Plants of the San Francisco Bay Region: Mendocino

to Monterey. Berkeley: University of California Press.

Chung, B. Y., Kim, J. H., Cho, S. I., Ahn, I. S., Kim, H. O., Park, C. W., & Lee, C. H. (2013, August).

Dose-dependent effects of evening primrose oil in children and adolescents with atopic

dermatitis. Retrieved from

Moore, M. (2003). Medicinal plants of the mountain West. Santa Fe: Museum of New Mexico


Scherer, C. A. (2003). The alchemy of the desert: A comprehensive guide to desert flower

essences for professional & self-help use. Tucson, AZ: Desert Alchemy Editions.

Schlichte, M. J., Vandersall, A., & Katta, R. (2016, July 31). Diet and eczema: A review of

dietary supplements for the treatment of atopic dermatitis. Retrieved from

Simpson, M. G. (2010). Plant systematics. Burlington, MA: Elsevier.

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