Beach Primrose

Camissoniopsis cheiranthifolia

Only a few plants can survive the harsh conditions of the coastal strand – the shifting, blowing strip of beach and sand dunes above the high tide line. This environment has been badly disturbed by development and recreational activities, and many of the coastal strand species have been declared threatened or endangered. In the Reserve, remnant coastal strand habitat persists in West Basin, between the railroad tracks and coast highway.

The beach primrose (Camissoniopsis cheiranthifolia ssp. suffruticosa) is one of our few coastal strand species. A dense covering of pale hairs protects it from the hot summer sun and a deep taproot and low-growing form anchor it against wind and shifting sand. In March and April, the yellow blossoms paint West Basin with bright stripes and patches.

Other Common Names:

Beach suncup, shrubby beach primrose, beach evening primrose

Description 2,3,4,11,26,59

Beach primrose is a low-growing, short-lived perennial subshrub that may form dense mats in sandy areas along the upper beach. Ataproot gives rise to a basal rosette of obovate to oblanceolate leaves and several wiry stems that hug the ground, curling up at the tip. Green stems turn reddish with age. Leaves are variable; basal leaves may be as long as 3 inches (8 cm); cauline leaves become progressively shorter and wider toward the stem tip; they often lack a petiole and clasp the stem directly. The leaves of our plantsgenerally have smooth edges, but leaves have also been described as wavy,59 or minutely toothed.4 Leaves and stems are more or less heavily covered with dense pale hairs.

Bright yellow flowers are produced in leaf axils near the terminal ends of the stems. Flowers are bisexual, radially symmetrical and usually 1 to 1.5 inches (22-37 mm) in diameter with four fan-shaped petals. A petal may have one or more red dots at its base. The four sepals are bent backwards and often joined in pairs. There are eight stamens, of unequal lengths; these are shorter than thepistil which has a long style capped with a spherical stigma. Aging blossoms turn an orange color. The main bloom period is April, but flowers may be found between Febrary and August.1

The ovary (and subsequent fruit) is below the flower and looks like the flower stalk (it is “inferior”). The fruit is a slim, four-sidedcapsule that coils once or more. The dried capsule splits open at the end allowing the seeds to be dispersed by gravity and animals. Dried capsules persist on the plant after splitting.

yellow flower with rounded leaves
orange/pink beach primrose bud on leafy branch
dry brown beach primrose bud curled up on branch

Distribution

Beach primrose is a California native plant found only along the immediate coast from central Oregon to northern Baja, usually less than 500 feet elevation.89  It is adapted to beaches, dunes and other sandy places above the tide line, and is only occasionally reported from slightly more inland locations.7 Much of its preferred habitat has been eliminated by development and recreational use.59

Our subspecies, ssp. sufffruticosa occurs primarily in coastal Southern California. The second subspecies, ssp. cheiranthifolia, is most abundant along the coast north of Point Conception, on the Channel Islands, and in northern Baja California.163

In the Reserve, beach primrose is common in the strand vegetation of West basin. When in bloom, the masses of yellow flowers are conspicuous from Coast Highway.

Classification

Beach primrose is a dicot angiosperm, which, in spite of its common name, is not a member of the primrose family (Primulaceae) but the evening primrose family (Onagraceae).2

Plants in the evening primrose family are characterized by radial, bisexual flowers with parts in multiples of four  (4 petals, 4 sepalsand 8 stamens).2,11,59,143 Other members of this family found in the Reserve include the delicate canyon clarkia (Clarkiaepilobioides) and the robust Hooker’s evening primrose (Oenothera elata ssp. hirsutissima).

Beach primrose was originally placed in the genus Oenothera. Along with several other species, they were moved into a new genus,Camissonia, on the basis of the structure of the stigma, which is spherical in Camissonia and X-shaped in Oenothera, and also by the fact that flowers of Camissonia open in daytime, rather than evening.59 Recently Camissonia was further split and beach primrose was moved to Camissoniopsis.

Two other species of Camissoniopsis have been reported from the Reserve: California suncup (C. bistorta) and Lewis’ evening primrose (C. lewisii).48

Two subspecies have been described for C. cheiranthifolia.2,7 Ours is ssp. suffruticosa.48 The second, ssp. cheiranthifolia, has smaller flowers, a shorter style with the stigma surrounded by anthers, and a distribution both north and south of the range of ssp.suffruticosa. The divergence of ssp. cheiranthifolia from ssp. suffruticosa is thought to have been associated with a change in pollination from insect-pollination (in ssp. suffruticosa) to self-pollination (in ssp. cheiranthifolia).163,164 This differentiation was accompanied by a change in flower morphology. Flowers of ssp. cheiranthifolia are smaller and paler, making them less visible to pollinators; the stigma is surrounded by the anthers, which facilitates self-pollination. It is postulated that the beach environments of  ssp. cheiranthifolia may be more variable and/or more extreme, making insects less reliable as pollinators.

Alternate Scientific Names:

Camissonia cheiranthifolia ssp. suffruticosa, Oenothera cheiranthifolia ssp. suffruticosa

Jepson eFlora Taxon Page
close-up of yellow beach primrose flower with 4 large rounded petals
Yellow beach primroses in full bloom
single yellow beach primrose flower on a small succulent plant in the sand

Ecology 165,166,167

Beach primrose is adapted to the coastal strand habitat of the upper beach and dunes. This is one of the harshest environments on earth. Plants must survive toxic salt spray, wind and sand scour, shifting substrate and the scorching temperatures of sand under summer sun. Both nutrients and water are scarce. Beach primrose is one of the few plants that thrive in the coastal strand environment.

Like most strand plants, beach primrose has a long taproot to anchor itself and numerous horizontal, radiating branches to hold the sand beneath. Leaves are small and densely covered with white hairs to reduce water loss and to reflect the summer sun. Growth and reproduction occurs during and following the winter rains and the plant is dormant during the hot, dry months of summer.

six yellow beach prim roses on vines stretching onto the sand
field of yellow beach primroses in full bloom with homes in the background
faraway shot of lagoon beach with small yellow beach primroses dotting the sand

Human Uses

Beach primrose is recommended for native plant gardens, especially in sandy soil.79 Given a bit of summer water, it may flower all year.168 It is often used in dune restoration work.23

Over-head shot of beach prim rose plant with a single yellow flower in the sand
Close up of yellow beach prim roses surrounded by green leaves
close up of four yellow beach prim roses on vines in the sand

Interesting Facts

Before the railroad and Coast Highway were built, the mouth of San Elijo Lagoon moved between the bluffs of Solana Beach to those of Cardiff-by-the-Sea. It was a dynamic environment, pounded by surf, blown by wind, and periodically flooded with freshwater from upstream. Much of the entrance was often closed by sand, and the estuary opening wandered, breaking through sand dunes at various places at different times. It was a functioning coastal strand environment, supporting a few highly adapted species of plants and animals. Unfortunately, the berms supporting the railroad and Coast Highway blocked the energy of wind and waves, and other plants became established in the less dynamic, more stable environment, crowding out the native vegetation. Coastal strand habitat began to disappear.

San Elijo Lagoon Conservancy is restoring a remnant of this rare coastal strand environment. While the full dynamics of dune habitat can not be recaptured, management of non-strand vegetation will allow the original species to recover. A four acre site in West Basin has been fenced off to limit foot and vehicular traffic. Much of the site has been cleared of desert arrowweed (Pluchea sericea), a plant that is native to California desert environments but thrives in relict coastal strand habitats where it is protected from the scouring activity of wind and waves. Non-native invaders, such as ice plant (Carpobrotus edulis), statice (Limonium sinuatum and L. perezii) and sea rocket (Cakile maritima) are being controlled. Beach primrose populations are thriving, along with sand verbena (Abronia umbellata var. umbellata), and there are recovering populations of three endangered dune species: Orcutt’s pincushion (Chaenactis glabriuscula var. orcuttiana), Nuttall’s lotus (Acmispon nuttallianus) and coast wooly-heads (Nemacaulis denudatavar. denudata).

over-head shot of beach primrose plant with a single yellow flower in the sand
Young man with a tan hat and red plaid shirt sitting in the sand reading notes
blue and white sign that reads "Birds Only Beyond This Point" on the shore of the lagoon

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