California Croton

Croton californicus

Overview

Overview

California croton (Croton californicus) is a low-growing, grayish-green plant with small, inconspicuous flowers. Male and female flowers occur on different plants. California croton is native to the southwestern United States and northern Mexico. It is a plant of sandy areas and can be seen in several low, sandy areas in the Reserve.

In spite of its generally drab appearance, the foliage is covered with a carpet of shining stellate hairs, each a tiny starburst. The hairs not only deter grazers, but also protect the plant from the environment; they reflect the sun, thereby cooling the plant, and they protect the leaves from the full force of the wind, thereby reducing water loss.

                            

Description

Description 2,4,11,26,59

California croton is a low-growing, short-lived perennial, woody at the base. Plants reach three feet (1 m)  high, but those in the Reserve usually hug the ground. The foliage,  stems and fruit are grayish-green and covered with tiny, scale-like, star-shaped hairs that give the plant a sheen. Leaves are oval to ovate, usually less than 2 inches (5 cm) long and 1 inch (2.5 cm) wide with smooth margins.

Male and female flowers are produced on separate plants. The inconspicuous greenish-white colored flowers occur in clusters of few to many flowers
at the leaf axils toward the ends of branches. Flowers are small, about 1/8 inch (0.3 cm) across, and lack petals; the sepals form a shallow cup with five lobes. The male flower has 10-15 stamens; the female flowerhas a pistil with a three-lobed ovary and three styles, each of which is branched into several (<9) terminal, tentacle-like segments. The reported flowering time is April - July,7 but flowers may be found all year.

The fruit is a three lobed capsule with an irregularly bumpy surface. When mature, it splits into three segments from the central axis, each segment releasing one seed. Seeds are a somewhat compressed ovoid, smooth and more or less mottled, with a fleshy appendage near the point of attachment (caruncle or elaiosome).

          

Other Common Names: 
desert croton

Distribution

Distribution

California croton occurs below 4000 feet in the southwestern United States and northern Mexico.89 In California it is found throughout the southern and central part of the state except for the Central Valley.7 It is common in coastal strand habitats,4,59 deserts89 and in other dry, sandy areas.11 California croton avoids clay soils and those with high organic content.59

In the Reserve California croton is found in low sandy areas along the south side trail especially in Central Basin near the eastern end of the Gemma Parks loop and in East Basin between the Santa Helena and La Orilla trailheads. Only a few California croton grow in West Basin, which is surprising in view of this croton's reputation as a coastal strand plant.

 

This plant occurs primarily in the following vegetation types in the San Elijo Lagoon Ecological Reserve: 
Chaparral
Coastal sage scrub
Coastal strand

Classification

Classification 11,44,59,143

Croton is a member of the spurge family (Euphorbiaceae). This is a large, diverse group containing small herbs, vines, cactus-like succulents, shrubs and trees. Many euphorbias contain a clear or milky sap that is toxic or irritating. Flowers often lack petals, although some species have colorful bracts or glands that function as petals. Flowers are unisexual. Male and female flowers may be on the same plant (plants are "monoecious") or on separate plants (plants are "dioecious"). The male flowers may have numerous stamens. The pistil of the female plant has three styles; the superior ovary is usually three-lobed and ripens into a dry three-chambered capsule that splits open on maturity releasing one seed per chamber.

The spurge family contains a variety of decorative, useful and annoying species, including the cheerful, holiday poinsettia (Euphorbia pulcherrima), the entertaining Mexican jumping bean (Sebastiania pavoniana), the deadly castor bean (Ricinus communis) and the omnipresent garden weed, spotted spurge (Euphorbia maculata). Other native euphorbias in the Reserve are dove weed, (Croton setiger), and cliff spurge (Euphorbia misera). Non-natives include castor bean and a variety of weedy species, including the spotted spurge.

The genus Croton is a very large and complicated genus. Recently, The Croton Project was established to bring botanists and ecologists together to clarify the taxonomy and phylogeny of the genus.218 Currently, members of the Croton genus are characterized by the development of the stamens and, to a large extent, by the presence of stellate hairs. Unlike many members of the spurge family, California croton lacks milky sap and is not known to be toxic.209 However, there are colorful house plants also called croton (Codiaeum spp.) that contain "quite a cocktail of bad stuff" which cause dermatitus and, if ingested, can be toxic to both  pets and humans.215,216 

         



 

Alternate scientific name(s): 
C. californicus var. tenuis C. californicus var. mohavensis

Ecology

Ecology 41,217

Many plants have hairs on their stems and/or leaf surfaces. These are thought to protect the plant by physically impeding chewing insects. Certainly the network of stellate hairs on the Croton leaf would appear to be a formidable barrier for a small grazer.

In our climate, where the summers are long and dry, an equally important purpose may be to protect the plant from environmental extremes. Hairs reflect the hot sun from the leaf surface, keeping the leaf cool, and they shelter the leaf surface from desiccating winds, reducing water loss.

        

Human Uses

Human Uses

In Southern California and northern Baja, native Americans used crotin for a variety of medical problems. Locally, the Kumeyaay made a tea of the entire plant and used it as an eye wash and a treatment for pink eye.16 In Baja, they drank a tea for a cough,219 and the Chumash drank a tea for "colds".15 The Luiseño used crotin to induce abortion.17 Other tribes made a salve which was rubbed on the skin for rheumatism,15 or used as a poultice for earaches.
34

          

Interesting Facts

Interesting Facts 21

The genus name, Crotin, is derived from the Greek word for "tick". Apparently seeds of some species of Crotin resemble those tiny, unpleasant parasites.

            

Photos

Central Basin, south side (Rios trailhead); Oct. 2015
East Basin, south side (Santa Helena trailhead); Oct. 2015
Central Basin, south side (Rios trailhead); Oct. 2015; photo courtesy of Mark Jenne
Central Basin, south side (Rios trailhead); Sept. 2015
East Basin, south side (Santa Helena trailhead); Sept. 2015
female plant; Central Basin, south side (Rios trailhead); June 2010
female plant; East Basin, south side (Santa Helena trailhead); Aug. 2010
female plant; East Basin, south side (Santa Helena trailhead); Nov. 2015
female plant; East Basin, east end (La Orilla trailhead); Nov. 2015
male plant; East Basin, south side (Santa Helena trailhead); June 2014
male plant; East Basin, south side (Santa Helena trailhead); Sept. 2015
male plant; Central Basin, south side (Rios trailhead); Nov. 2015
male flower at 30X; East Basin, south side (Santa Carina trailhead); Sept. 2015
female plant; Central Basin, south side (Rios trailhead); Oct. 2015
developing fruit; Central Basin, south side (Rios trailhead); Oct. 2015
stem gall on California crotin; Central Basin, south side (Rios trailhead); Nov. 2015
stellate hairs on leaf; Central Basin, south side (Rios trailhead); Sept. 2015
stellate hairs on leaf; Central Basin, south side (Rios trailhead); Oct. 2015
seed; Central Basin, south side (Rios trailhead); Nov. 2015
seed with elaiosome at lower end; Central Basin, south side (Rios trailhead); Nov. 2015