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Wavy-leafed Soap Plant

Chlorogalum pomeridianum

Summary 3

Chlorogalum pomeridianum, the wavy-leafed soap plant, California soaproot, or Amole, is the most common and most widely distributed of the soap plants, soaproots or amoles, which make up the genus Chlorogalum of flowering plants. It is occasionally known as the "wild potato", but given the plant's lack of either resemblance or relationship to the potato, this name is not recommended.

Subspecies 4

Three varieties are recognized:

The basionym of the species was Scilla pomeridianum. It has also been known as Laothoe pomeridiana.

Description 4

Like all the soap plants, Chlorogalum pomeridianum is a perennial that grows from a bulb, which is brown, between 7 and 15 cm in diameter, slightly elongated, and covered in thick, coarse fibers. The leaves grow from the base of the plant, and can be from 20 to 70 cm long and 6 to 25 mm wide. As the plant's name indicates, their edges are generally wavy, though this is not always particularly noticeable.

The flowers are borne on a long stem, normally longer than the leaves, and are from 15 to 30 mm long. The six petals (actually only three of them are petals in the technical sense; the other three are sepals) are up to 35 mm long and curving. They are typically white but have a noticeable mid-vein which can be purple or green in color. The six stamens are large and noticeable, and yellow or orange. The flowers are bisexual (include both female and male parts).

They open only in the late afternoon or evening, remaining open during the night but closing by the morning. Pollination is by evening- or night-flying insects.

Three varieties are recognized:

The basionym of the species was Scilla pomeridianum. It has also been known as Laothoe pomeridiana.

Habitat characteristics 5

More info for the terms: forb, natural, serpentine soils

Soap plant is an abundant forb, common throughout coastal sage scrub, chaparral, and coastal terrace prairies [12,39,52,55]. It occurs on dry, open woodlands and rocky hillsides, bluffs, and grasslands [11,13,25,30,38,39,52]. It most commonly occurs, however, on burned and unburned chaparral [18,24,36,53] on shallow, rocky, serpentine soils [47]. Sweeney [57] adds that soap plant is abundant and widespread on burns and on open and disturbed sites adjacent to burns. Other common occurrences are under dense brush, near edges of brush, and on partly open sites within brush stands. In Pinnacles National Monument, soap plant is found on south-facing slopes that are drier and have typically shallower soils compared to other chaparral communities [22].

The climate in which soap plant thrives is described as mediterranean [47], with cool, wet winters and warm, dry summers [22]. The mean annual precipitation ranges from 16 to 20 inches (410 -510 mm) [46].

The following table provides elevations where soap plant has been collected. Location Elevation California below 5,000 feet (1,524 m) [25,38,52] Elk Creek Drainage (Sequoia National Park) 2,100 feet (640 m) [53] Hastings Natural History Reservation, San Lucia Coastal Range, Monterey County 860 to 3,600 feet (262-1,050 m) [54] central Sierra Nevada up to 6,000 feet (1,800 m) [44] Pinnacles National Monument 1,200 to 3,000 feet (370-910 m) [22] Donald and Sylvia McLaughlin University of California Natural Preserve 1,200 to 3,100 feet (370-950 m) [47] Santa Ana Mountains average 3,500 feet (1,100 m) [60] Oregon below 5,000 feet (1,524 m) [25]

Distribution 6

Soap plant is a narrow endemic. Distribution is limited to the southwest corner of Oregon southward into southern California [31]. The Flora of North America  provides a distributional map for soap plant and its varieties.

Populations of Chlorogalum pomeridianum var. divaricatum and C. p. var. minus are documented only in California. Chlorogalum p. var. pomeridianum occurs in California and Oregon [59].

Fire ecology 7

More info for the terms: bulb, frequency, selection, shrubs

Fire adaptations: Soap plant sprouts and seeds after fire. The perennating part of soap plant is a deeply buried, large bulb, which is its 1st defense against fire [10,20]. Second, soap plant is said to have an evolved fire-adaptive trait of "fire-stimulated flowering," since it flowers the 1st growing season after fire. Flowering is virtually absent beforehand [9,20]. Gill [20] states that flowering responses to fire may have arisen by direct selection for increased seed production but the significance of the trait could be related to various environmental pressures. For example, increased flowering and seed production after fire allows use of the available mineral seed bed, enhancing establishment. Alternatively, cyclic flowering stimulated by the passage of frequent fire could prevent the build-up of populations of specific predators to inflorescences, so successful reproduction can occur. Lastly, pollination could be favored by the removal of shrubs and the subsequent increase in light [20].

FIRE REGIMES: Soap plant occurs in a narrow range of FIRE REGIMES. Chaparral communities, where soap plant is common, sustain frequent, stand-replacing fires. The high frequency of fire in chaparral communities suggests that soap plant has evolved with fire. The oak woodland and low-elevation ponderosa pine communities, in which soap plant also occurs, historically had frequent, low-severity fires. In ponderosa pine and some oak communities, low-severity surface fires are being replaced by high-severity, long-interval fires [8].

The following table provides fire return intervals for plant communities and ecosystems where soap plant is important. For further information, see the FEIS review of the dominant species listed below. Community or ecosystem Dominant species Fire return interval range (years) California chaparral Adenostoma and/or Arctostaphylos spp. <35 to <100 coastal sagebrush Artemisia californica <35 to <100 California montane chaparral Ceanothus and/or Arctostaphylos spp. 50-100 [40] California steppe Festuca-Danthonia spp. 40,55] Jeffrey pine Pinus jeffreyi 5-30 Pacific ponderosa pine* Pinus ponderosa var. ponderosa 1-47 California mixed evergreen Pseudotsuga menziesii var. menziesii-Lithocarpus densiflorus-Arbutus menziesii <35 California oakwoods Quercus spp. <35 [3] coast live oak Quercus agrifolia 2-75 [21] canyon live oak Quercus chrysolepis <35 to 200 blue oak-foothills pine Quercus douglasii-P. sabiniana <35 Oregon white oak Quercus garryana <35 [3] California black oak Quercus kelloggii 5-30 [40] *fire return interval varies widely; trends in variation are noted in the species review

Uses 4

The fibers surrounding the bulb were widely used, bound together, to make small brushes. Extracts of the bulbs could also be used as a sealant or glue.

The juices of the bulb contain saponins that form a lather when mixed with water, and both Native American people (e.g. Miwok tribe) and early European settlers used the bulbs as a kind of soap; this is the origin of the plant's name. It was particularly used for washing hair, since it was held to be effective against dandruff.

The young leaves can be used as food, but the saponins in the bulbs make these poisonous. However saponins are very poorly absorbed by the body and usually pass straight through, and in any case they can be destroyed by thorough cooking. The Miwok people roasted and ate the bulbs as a winter food. In February 1847 Patrick Breen of the ill-fated Donner Party recorded that a Native American gave the starving settler some "roots resembling Onions in shape [that] taste some like a sweet potatoe [sic], all full of little tough fibres." Breen's son later called the roots "California soap-root"—almost certainly C. pomeridianum.

Saponins are much more toxic to some other animals than they are to humans. Fish are particularly susceptible, and the bulb juices were used to kill or stun them so they could be caught easily.

The bulbs also had various medicinal uses, both external (e.g., for making a poultice to be used as an antiseptic, or as a rub in cases of rheumatism) and internal (decoctions were used for a range of purposes, including as a diuretic, as a laxative and against stomachache).

Sources and Credits

  1. (c) Ken-ichi Ueda, some rights reserved (CC BY), uploaded by Ken-ichi Ueda, http://www.flickr.com/photos/18024068@N00/2546628711
  2. (c) charlie dubbe, some rights reserved (CC BY-NC), uploaded by charlie dubbe
  3. Adapted by dlimandri from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Chlorogalum_pomeridianum
  4. (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Chlorogalum_pomeridianum
  5. Public Domain, http://eol.org/data_objects/24628101
  6. Public Domain, http://eol.org/data_objects/24237141
  7. Public Domain, http://eol.org/data_objects/24628103

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