Soap Lilies In California

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Noteworthy Plants December (1) 1998

Soap Lilies In California

Bulb Plants Used For Soap and Food

These unusual bulbs grow wild in the dry, rocky hillsides north and west of Palomar College, in an endangered plant community known as coastal sage scrub. In the tradition of Noteworthy Plants, they have intrigued biology and botany students of Mr. Wolffia for many decades.


The Lily Family (Liliaceae) includes about 300 genera and 4600 species distributed throughout the world, especially in dry temperate and subtropical regions. Some botanists have placed many of the genera into separate families, such as the Agave Family (Agavaceae) and Amaryllis Family (Amaryllidaceae). Although it is not as large as the Orchid Family (Orchidaceae), the Lily Family has some spectacular representatives with flowers that are as large and beautiful as some orchids. Lilies are cultivated for their showy blossoms, and some species are grown for food, alcoholic beverages and strong leaf fibers. One of the most unusual uses for members of this large plant family is soap. In fact, California has five species and five varieties of true "soap lilies" (Chlorogalum). Two of these species occur in the coastal sage scrub plant community adjacent to Palomar College. They were used extensively by native Indian tribes and early settlers of this region. Several other plant species in different and unrelated plant families were also used for soap in other parts of the world.


According to the Jepson Manual of Higher Plants of California (1993), five species of soap lilies (Chlorogalum) are native to California: C. angustifolium, C. grandiflorum, C. purpureum, C. parviflorum, and C. pomeridianum. According to most ethnobotanical references on the early uses of California plants, (C. parviflorum and C. pomeridianum) were commonly used for food and soap by native Indians and early settlers, especially the latter species. Both species occur in the cismontane (coastal) mountains, valleys, and mesas of southern California. Chlorogalum pomeridianum occupies dry open hills and plains below 5,000 feet (1500 m), chiefly in the valley grassland, coastal sage scrub, chaparral and foothill woodland plant communities, from southern Oregon to San Diego County, California. C. parviflorum occurs in dry open places below 2,000 feet (600 m), chiefly in the valley grassland and coastal sage scrub plant communities from Los Angeles County to Riverside and San Diego Counties and northern Baja California. C. parviflorum often grows on dry, barren ridges or bluffs within coastal sage scrub, while C. pomeridianum typically grows in valley grassland and more sheltered (shady) sites in the coastal sage scrub and chaparral.

Two distinct species of soap lilies in California: Chlorogalum pomeridianum (left) and C. parviflorum (right). C. pomeridianum has larger bulbs that are covered with long brown fibers.

Chlorogalum purpureum var. reductum

A rare, purple-flowered species of soap lily native to the coastal ranges of Central California. Unlike the other white-flowered species of soap lilies native to California, this small, seldom-seen species has purple flowers. It grows in hard-packed, gravelly and pebbly soils in the La Panza Range of San Luis Obispo County. This is the only known location of this species in the wild. Another rare variety (var. purpureum) is only known from five locations near Jolon (Monterey County) on the Hunter Liggett Army Base, and at Camp Roberts in San Luis Obispo County.

The rare Camatta Canyon amole (Chlorogalum purpureum var. reductum).


Soap lilies (Chlorogalum) are acaulescent herbs with tufted basal leaves arising from a scaly bulb that produces a tall, leafless paniculate inflorescence. The small white flowers are often subtended by a scarious bract at the base of each pedicel. Each flower consists of six perianth segments composed of three outer sepals and three inner petals which are very similar in size and shape. The perianth segments commonly have a darkened midvein and become twisted together and persistent above the developing fruit (capsule). The flowers also consist of six stamens and a hypogynous ovary forming a loculicidal 3-valved seed capsule. The following table shows the main diagnostic taxonomic differences between C. pomeridianum and C. parviflorum:

C. pomeridianum

C. parviflorum     

Bulbs 7-15 cm long; heavily coated with dark brown fibers. Bulbs 4-7 cm long, covered with brown membranous coat.
Leaves 20-70 cm long and 6-25 mm wide; very wavy (undulate). Leaves 10-20 cm long and 3-9 mm wide; leaf margin undulate.
Flower stalk 60-250 cm tall. Flower stalk 30-90 cm tall.
Perianth segments 15-23 mm long. Perianth segments 6-8 mm long.
Flowers vespertine (nocturnal). Flowers diurnal.

Although the flowers and bulbs of C. pomeridianum are larger than those of C. parviflorum, what really sets these two species apart are the unmistakable bulb coats. Bulbs of C. pomeridianum are covered with long, brown fibers, while those of C. parviflorum have a brown, membranous coat. Although both species bloom during the late spring and summer months, the flowers of C. pomeridianum open at night, while those of C. parviflorum open during the daylight hours. In addition, the leaves of C. pomeridianum are longer and wider.

The flowers of Chlorogalum pomeridianum are seldom observed in full bloom because they open at dusk. They are undoubtedly pollinated by night-flying insects such as small moths.

Soap lily (Chlorogalum pomeridianum) in Kern County, California.

The flowers of Chlorogalum parviflorum open during the daylight hours. As the specific epithet "parviflorum" implies, they are smaller than the other common soap lily (C. pomeridianum).

Soap lily (Chlorogalum parviflorum) in San Diego County, California.

The only other lily within the range of soap lilies that might be confused with Chlorogalum is the star lily Zigadenus. Star lilies (Zigadenus fremontii) commonly grow in the sage scrub and grasslands of coastal mesas where soap lilies thrive. These two genera should not be confused because some species of Zigadenus (also called death camas) are quite poisonous to cattle, sheep, and humans if ingested (Fuller and McClintock, 1986). The bulbs contain zygadenine, a very toxic steroidal alkaloid. In fact, Zigadenus was one of the few genera in which bulbs were not eaten by native Indians (Balls, 1970). According to Fuller and McClintock (1986), one or two pounds of death camas may kill a 100 pound sheep. Bulbs of death camas made into flour caused serious illness to members of the Lewis and Clark expedition. Although its native range is quite different, the desert lily (Hesperocallis undulata) has basal undulate (wavy) leaves which are remarkably similar to those of Chlorogalum. Unlike the poisonous Zigadenus, the bulbs of both Chlorogalum and Hesperocallis were used for food by the native Indian tribes of southern California.

The range of this star lily (Zigadenus fremontii var. minor) coincides with both species of soap lilies in coastal California. Star lily bulbs contain a very poisonous alkaloid called zygadenine.


Saponins are a group of glucosides found in several plant species and are characterized by their soap-like property of foaming in a water solution. Glucosides (or glycosides) are plant compounds containing glucose (or another sugar) combined with other non-sugar molecules. Upon hydrolysis saponin glycosides yield a triterpenoid or steroid sapogenin and one or more sugars, such as glucose, galactose, or xylose (Bonner and Varner, 1965). Saponins lower the surface tension of aqueous solutions and form colloidal dispersions in water. When shaken they produce a nonalkaline soap-like froth. The amount of foam produced is a rough indication of the amount of saponins present in the solution.

Saponin in powder form has as its active ingredient the triterpenoid component which is used chiefly as a foaming and emulsifying agent. Triterpenoid saponins have been used in the manufacture of foam fire extinguishers, toothpaste, foam in beverages (including soft drinks and beer), shampoos, liquid soaps, and cosmetic preparations. Steroidal sapogenins are of interest because of the possibility of using them as a starting material (precursor) for the synthesis of certain steroidal hormones (Miller, 1957).

Unlike the cardiac glucosides, saponins do not affect the heart. Saponins are especially toxic to fish, and thus have attained a wide use as fish poisons (Kirk, 1954). The toxin acts on the respiratory organs of fish without affecting their edibility. Saponins also result in the break down (hemolysis) of red blood cells (erythrocytes) and may be fatal when solutions are injected into the bloodstream of animals (Miller, 1957).

According to Muenscher (1961), several types of glucosides yielding toxic products upon hydrolysis occur in widely unrelated families. The most important groups of glucosides concerned in plant poisoning are cyanogenic glucosides, saponin glucosides, solanines, and mustard oil glucosides. Saponins are found in a number of plants considered poisonous to livestock and humans if ingested. The degree or severity of poisoning may be due to the type or amount of saponin ingested or the particular products of hydrolysis.

As mentioned previously, several plants in addition to Chlorogalum contain saponins and some are economically important. These include the soapbark tree (Quillaja saponaria), soapwort (Saponaria officinalis), and the soapberry (Sapindus saponaria). Due to the toxic nature of saponins and their hemolysis of red blood cells, its use to increase the foaming power of beer and other beverages has been discouraged (Hill, 1952).

An aqueous solution of soapberry fruits that has been vigorously shaken. The foaming action is caused by saponins present in the leathery fruit walls (pericarp). The three shiny round structures (lower left) are soapberry seeds, known in Central America as "black pearls."

The soapberry tree is native to southern Arizona, New Mexico and Texas, extending south through Mexico, Central and South America. The leathery brown berries are rich in saponins, glycosides containing glucose or a related sugar plus a toxic triterpenoid component. They have the property of foaming with water and have been used as soap in Mexico and tropical America. In addition, saponins are especially toxic to cold-blooded vertebrates, and crushed soapberry fruits were thrown into ponds and streams to stupefy the fish so that they would float to the surface to be gathered. Perhaps the most fascinating part of the fruits are the black, marble-like seeds. Known as "black pearls" throughout the American tropics, the shiny seeds are used extensively in necklaces, bracelets and earrings.

The shiny black seeds, leathery one-seeded fruits and mature leaf of the soapberry tree (Sapindus saponaria). The hard seeds are known as "black pearls" and are strung into bracelets and necklaces in Central America.

A soapberry seed necklace (Sapindus saponaria) from the Hawaiian Islands. This widespread species of tree occurs in the southwestern United States, Mexico and South America, west across the Pacific Basin on a number of islands to New Caledonia. On the island of Hawaii it grows in mesic forests on Hualalai, Mauna Loa and Kilauea. It also occurs in Africa where the seeds are used in the board game called mancala.

Read About The Board Game Called Mancala or Wari


The amole or soap plant (Chlorogalum pomeridianum) was widely used by native Indian tribes of southern California, including the Diegueno, Luiseno, and the Cahuilla. One important use of this plant is depicted by its common name of soap plant or soap lily. The outer scales and fibers were removed from the bulbs. Crushed bulbs rubbed on the hands or clothing produced a lather when rubbed vigorously with water. Bulbs were considered to be an excellent shampoo, leaving the hair soft and glossy, and were said to be useful in removing dandruff (Balls, 1970). A Palomar College general biology student reported a slight problem with pieces of the bulb scales in her hair after shampooing with a local soap lily. This problem may have been the result of her technique. The bulbs contain a saponin which is also found in the soapberry tree (Sapindus). The lather does not contain alkali and is especially good for washing delicate fabrics.

The bulbs of soap lilies were also used for food. They were roasted with fibers and scales in place, then peeled and eaten, or peeled and boiled prior to eating. The bulbs were baked in stone-lined pits. Bulbs put into the oven at night were ready by the following morning. The "earth ovens" consisted of a pit dug into the ground, lined with rocks, and heated by building a fire in it. When the rock lining was thoroughly heated, the fire was raked out and the bulbs were placed in the hot pit, covered with leaves, and then banked over with earth and sometimes more rock. According to Balls (1970), the leaves of poison oak (Rhus diversiloba) were used by the Karok Indians of northwestern California to cover the bulbs while baking them in the earth ovens. The slow cooking destroyed the soapy nature of the bulbs leaving a good nourishing food. The course fibers covering the bulbs were used in making brushes for sweeping the fine flour out of the inside of the basket-hopper used in the process of grinding acorn flour. The fibers of C. pomeridianum were also used for sweeping out the bed rock mortars and baskets by the Cahuilla Indians (Bean and Saubel, 1972).

According to Balls (1970), the young spring shoots of soap lilies were very sweet when cooked by the slow process of the pit oven. While still young, the fresh green leaves were also eaten raw. Older leaves were largely used for wrapping acorn bread during baking. Medicinally, the roasted bulbs were used as poultices for sores, and the fresh crushed bulb was rubbed on the body to cure rheumatic pains and cramps. The thick mucilaginous sap that oozed out of the baking bulbs was used as a glue for attaching feathers to arrow shafts and was smeared over the wood of a new bow to take a covering of soot to make the new bow look old (Balls, 1970). It was also smeared on baskets to make them watertight. In addition, the juice from the leaves was also pricked into the skin to make green tattoo markings.

Wavy (undulate) leaves of a soap lily (Chlorogalum pomeridianum var. minus) in coastal central California. The shiny green rock is serpentine, an interesting formation in California associated with endemic plant species.

The crushed green plant, including the bulb, was used in streams to stupefy fish (Kirk, 1970). Large numbers of fish were caught by throwing the crushed or powderd bulbs into carefully dammed streams. As the fish floated to the surface they were picked out by hand or with a coarse-meshed net. This cooperative fishing, where the whole village worked together, meant that great quantities of bulbs would be prepared at one time. According to Balls (1970), all the fish including eels (not frogs) were stupefied. Apparently the harvesting of fish in this manner had no ill effects on those who ate the fish. The fish were washed to remove any traces of the crushed bulbs from their gills. Other plants have been used to stupefy fish in California but none so widespread as Chlorogalum. This method of catching fish has been employed by natives in other parts of the world. It is illegal in California today because it wipes out fish of all age groups--thus rapidly depleting the vital populations of fish in streams and lakes.

Several other plants that occur in the same general range as Chlorogalum were used in similar ways. The entire foliage and roots of dove weed or turkey mullein (Eremocarpus setigerus) were crushed and thrown into streams to stupefy the fish. The large perennial taproots of goosefoot or pigweed (Chenopodium californicum) were used for soap. In fact, the ground up roots were used in the same way as modern soap powder. Both of these species are common in the coastal sage scrub plant community north of Palomar College.

The perennial taproot of the native goosefoot (Chenopodium californicum) contains saponins and was used for soap by early California settlers.

Summary And Conclusions

Soap lilies (Chlorogalum) were widely used and extremely important plants to Indian tribes of southern California as well as other parts of the state. This includes the Luiseno and Diegueno Indians of the coastal regions of San Diego County; and the Cahuilla Indians of the inland valleys and desert regions. The bulbs were used for food, soap, glue, fish poison, and brushes. According to Munz (1961), the bulbs contain an abundance of starch and are an excellent source of carbohydrates. Other parts of the plant, such as leaves and stems, were eaten or used as a green die in tattoos. Most authors cited in this article refer to the species C. pomeridianum which has a much wider range, extending from southern Oregon to southern California. However, in the dry coastal mesas of San Diego County and Baja California, C. parviflora appears to be locally more common and abundant. Since the flowers of C. pomeridianum are nocturnal and relatively short-lived, the nature of the bulb is an excellent means of identification when inflorescences are not available during much of the year.

One final point of interest is how native people dug up the bulbs of soap lilies. The bulbs may be 15-20 centimeters deep and are extremely difficult to dig out of hard, compact sandstone or decomposed granite--even with a full-sized shovel. Considering all the uses made from this plant, the bulbs must have been dug up in quantity. Perhaps the Indians dug out the bulbs following rainy seasons in the spring while the ground was still moist. According to Munz (1961), the long narrow leaves appear after the first autumn rains and remain for many months. So bulbs could be found throughout much of the year even when flower stalks were not visible.


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  15. Munz, P.A. 1961. California Spring Wildflowers. University of California Press, Berkeley.

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