Chlorogalum purpureum
Encyclopedia
Chlorogalum purpureum is a species of flowering plant related to the agave
s known by the common name purple amole. This species of soap plant is endemic to California
where it grows in the mountain ranges of the Central Coast
. There are two varieties of this plant, and both are believed to be quite rare. It is a federally listed threatened species
.
about 3 centimeters in diameter. The narrow, wavy leaves grow at the base of the stem. The leaves are bright green and have thick midribs. There are usually one to eight leaves, but plants with up to fourteen have been noted. The stem bears flowers at widely spaced nodes. Each flower has curled tepal
s each less than a centimeter long in shades of blue or purple; all other Chlorogalum species have white or pink flowers. The flowers have long stamen
s with yellow anthers around a protruding style
.
The two varieties of the species can be told apart by their sizes; var. purpureum (the variety usually called purple amole) grows up to 40 centimeters tall and var. reductum (Camatta Canyon amole) reaches only 20 centimeters. About 90% of the plants are of var. purpureum.
with hot, rainless summers and wet winters. Purple amole, var. purpureum, is endemic to the Santa Lucia Range of Monterey
and San Luis Obispo Counties
. It is known from only two locations, the Army
installation Fort Hunter Liggett
and the National Guard
post Camp Roberts
. There are a total of four populations, probably totalling under 10,000 total individuals. The habitat is grassland
with patches of oak woodland
. The Camatta Canyon amole, var. reductum, is known only from the La Panza Range
in the center of San Luis Obispo County, about 61 kilometers away from the nearest population of purple amole. There is a single population with a variable number of individuals. The population sizes are difficult to estimate because the plants bloom infrequently and go dormant for several seasons at a time.
Both varieties of this plant grow in soil lined with cryptogamic crust
s. Purple amole is often associated with undisturbed or recovering soil crusts dominated by cyanobacteria. The soils beneath are clay topped with loam
and a gravel
ly top layer. Much of the habitat is fragmented
due to a history of crop cultivation
in the area. Plant associates in the area include rusty popcornflower
(Plagiobothrys nothofulvus), miniature lupine
(Lupinus bicolor), California goldfields
(Lasthenia californica), and yellowflower tarweed
(Holocarpha virgata), as well as another soap plant species, wavyleaf soap plant
(Chlorogalum pomeridianum).
Camatta Canyon amole grows in dry, pebbly, red clay soils; though some sources state this plant is part of the serpentine soil
s flora, it is actually more often found in a unique form of laterite
, and never serpentine. Floral associates include crown brodiaea
(Brodiaea coronaria), bluedicks
(Dichelostemma capitatum), winecup clarkia
(Clarkia purpurea), and sometimes chamise
(Adenostoma fasciculatum).
There is a positive correlation between winter rainfall amounts and the number of purple amole that bear flowers the following spring.
s, which consume the plants, and feral pigs, which eat the bulbs and trample the habitat. Camatta Canyon amole occurs in an area used by off-road vehicle
enthusiasts and herds of grazing cattle; these two forces tend to damage cryptogamic soil crusts and encourage the invasion of non-native plants
. Invasive plants are a main threat to both varieties, as they outcompete
them and change the local fire regime
; the Camatta Canyon amole occurs in a single clumped, localized population that could be reduced significantly in a wildfire
. Other suggested threats to the species include military activities and road maintenance.
Agave
Agave is a genus of monocots. The plants are perennial, but each rosette flowers once and then dies ; they are commonly known as the century plant....
s known by the common name purple amole. This species of soap plant is endemic to California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
where it grows in the mountain ranges of the Central Coast
Central Coast of California
The Central Coast is an area of California, United States, roughly spanning the area between the Monterey Bay and Point Conception. It extends through Santa Cruz County, San Benito County, Monterey County, San Luis Obispo County, and Santa Barbara County...
. There are two varieties of this plant, and both are believed to be quite rare. It is a federally listed threatened species
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
.
Description
This is a perennial plant growing from a bulbBulb
A bulb is a short stem with fleshy leaves or leaf bases. The leaves often function as food storage organs during dormancy.A bulb's leaf bases, known as scales, generally do not support leaves, but contain food reserves to enable the plant to survive adverse conditions. At the center of the bulb is...
about 3 centimeters in diameter. The narrow, wavy leaves grow at the base of the stem. The leaves are bright green and have thick midribs. There are usually one to eight leaves, but plants with up to fourteen have been noted. The stem bears flowers at widely spaced nodes. Each flower has curled tepal
Tepal
Tepals are elements of the perianth, or outer part of a flower, which include the petals or sepals. The term tepal is more often applied specifically when all segments of the perianth are of similar shape and color, or undifferentiated, which is called perigone...
s each less than a centimeter long in shades of blue or purple; all other Chlorogalum species have white or pink flowers. The flowers have long stamen
Stamen
The stamen is the pollen producing reproductive organ of a flower...
s with yellow anthers around a protruding style
Gynoecium
Gynoecium is most commonly used as a collective term for all carpels in a flower. A carpel is the ovule and seed producing reproductive organ in flowering plants. Carpels are derived from ovule-bearing leaves which evolved to form a closed structure containing the ovules...
.
The two varieties of the species can be told apart by their sizes; var. purpureum (the variety usually called purple amole) grows up to 40 centimeters tall and var. reductum (Camatta Canyon amole) reaches only 20 centimeters. About 90% of the plants are of var. purpureum.
Ecology and distribution
This is a plant of the Mediterranean climateMediterranean climate
A Mediterranean climate is the climate typical of most of the lands in the Mediterranean Basin, and is a particular variety of subtropical climate...
with hot, rainless summers and wet winters. Purple amole, var. purpureum, is endemic to the Santa Lucia Range of Monterey
Monterey County, California
Monterey County is a county located on the Pacific coast of the U.S. state of California, its northwestern section forming the southern half of Monterey Bay. The northern half of the bay is in Santa Cruz County. As of 2010, the population was 415,057. The county seat and largest city is Salinas...
and San Luis Obispo Counties
San Luis Obispo County, California
San Luis Obispo County is a county located along the Pacific Ocean in the Central Coast of the U.S. state of California, between Los Angeles and the San Francisco Bay Area. As of the 2010 census its population was 269,637, up from 246,681 at the 2000 census...
. It is known from only two locations, the Army
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...
installation Fort Hunter Liggett
Fort Hunter Liggett
Fort Hunter Liggett , named after General Hunter Liggett in 1941, is a United States Army fort in southern Monterey County, California, about 250 miles north of Los Angeles and south of San Francisco...
and the National Guard
California Army National Guard
The California Army National Guard is the land force component of the California National Guard, one of the reserve component United States Army and is part of the United States National Guard. The California Army National Guard is composed of about 20,000 soldiers...
post Camp Roberts
Camp Roberts, California
Camp Roberts is a California National Guard post in central California, located on both sides of the Salinas River in Monterey and San Luis Obispo counties, now run by the California Army National Guard. It is named after Harold W. Roberts, a World War I Medal of Honor recipient...
. There are a total of four populations, probably totalling under 10,000 total individuals. The habitat is grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
with patches of oak woodland
California oak woodland
California oak woodland is a plant community found throughout the California chaparral and woodlands ecoregion of California in the United States and northwestern Baja California in Mexico...
. The Camatta Canyon amole, var. reductum, is known only from the La Panza Range
La Panza Range
The La Panza Range is a mountain range in the Central Coast of California region in San Luis Obispo County, east of the small town of Santa Margarita. It is one of the California Coast Ranges and in the Los Padres National Forest....
in the center of San Luis Obispo County, about 61 kilometers away from the nearest population of purple amole. There is a single population with a variable number of individuals. The population sizes are difficult to estimate because the plants bloom infrequently and go dormant for several seasons at a time.
Both varieties of this plant grow in soil lined with cryptogamic crust
Cryptobiotic soil
A Cryptobiotic soil is a biological soil crust composed of living cyanobacteria, green algae, brown algae, fungi, lichens, and/or mosses. Commonly found in arid regions around the world, cryptobiotic soils go by many names, including cryptogamic, microbiotic, or microphytic soils or crusts...
s. Purple amole is often associated with undisturbed or recovering soil crusts dominated by cyanobacteria. The soils beneath are clay topped with loam
Loam
Loam is soil composed of sand, silt, and clay in relatively even concentration . Loam soils generally contain more nutrients and humus than sandy soils, have better infiltration and drainage than silty soils, and are easier to till than clay soils...
and a gravel
Gravel
Gravel is composed of unconsolidated rock fragments that have a general particle size range and include size classes from granule- to boulder-sized fragments. Gravel can be sub-categorized into granule and cobble...
ly top layer. Much of the habitat is fragmented
Habitat fragmentation
Habitat fragmentation as the name implies, describes the emergence of discontinuities in an organism's preferred environment , causing population fragmentation...
due to a history of crop cultivation
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
in the area. Plant associates in the area include rusty popcornflower
Plagiobothrys nothofulvus
Plagiobothrys nothofulvus is a species of flowering plant in the borage family known by the common name rusty popcornflower. It is native to western North America from Washington, and California, to northern Mexico, where it is a very common spring wildflower in grassy meadows, woodlands, and other...
(Plagiobothrys nothofulvus), miniature lupine
Lupinus bicolor
Lupinus bicolor is a species of lupine known as the miniature lupine, Lindley's annual lupine, or bicolor lupine. It is a showy flowering plant native to western North America from California to British Columbia. It is an annual lupine which often shares a habitat with the California poppy. It has...
(Lupinus bicolor), California goldfields
Lasthenia californica
Lasthenia californica is a species of flowering plant in the daisy family known by the common name California goldfields. It is native to California and Oregon and surrounding areas, where it is a very common member of the flora in a number of habitat types. This is an annual herb approaching a...
(Lasthenia californica), and yellowflower tarweed
Holocarpha virgata
Holocarpha virgata is a species of flowering plant in the aster family known by the common name yellowflower tarweed.-Description:Holocarpha virgata is an annual herb producing an erect stem 20 centimeters to over one meter tall. It has many branches and is lined with oily glands and hairs...
(Holocarpha virgata), as well as another soap plant species, wavyleaf soap plant
Chlorogalum pomeridianum
Chlorogalum pomeridianum, the Wavy-leafed Soap Plant or California soaproot, 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 found in most of California, apart from the Sierra Nevada and the...
(Chlorogalum pomeridianum).
Camatta Canyon amole grows in dry, pebbly, red clay soils; though some sources state this plant is part of the serpentine soil
Serpentine soil
A serpentine soil is derived from ultramafic rocks, in particular serpentinite, a rock formed by the hydration and metamorphic transformation of ultramafic rock from the Earth's mantle....
s flora, it is actually more often found in a unique form of laterite
Laterite
Laterites are soil types rich in iron and aluminium, formed in hot and wet tropical areas. Nearly all laterites are rusty-red because of iron oxides. They develop by intensive and long-lasting weathering of the underlying parent rock...
, and never serpentine. Floral associates include crown brodiaea
Brodiaea coronaria
Brodiaea coronaria is the type species of Brodiaea and also known by the common name crown brodiaea. It is native to western North America from British Columbia to northern California, where it grows in mountains and grasslands.-Description:...
(Brodiaea coronaria), bluedicks
Dichelostemma capitatum
Dichelostemma capitatum , called Blue dicks, Purplehead and Brodiaea occur in Arizona, California, Oregon, Utah, New Mexico, and northern Mexico.-Subspecies:...
(Dichelostemma capitatum), winecup clarkia
Clarkia purpurea
Clarkia purpurea is a species of wildflower known by the common names winecup clarkia, winecup fairyfan, and purple clarkia. This plant is native to western North America where it is found in a variety of habitats. This plant erects a thin reddish stem which may approach a meter in height and has a...
(Clarkia purpurea), and sometimes chamise
Adenostoma fasciculatum
Adenostoma fasciculatum is a flowering plant native to California and northern Baja California. This shrub is one of the most widespread plants of the chaparral biome.-Description:...
(Adenostoma fasciculatum).
There is a positive correlation between winter rainfall amounts and the number of purple amole that bear flowers the following spring.
Conservation
This plant has a limited distribution in two counties. The two populations of purple amole are secure from destruction or development of their habitat. Other potentially damaging forces include gopherGopher
- Animal kingdom :* Gopher , including:** Pocket gophers , about 40 species distributed from North America to Colombia** Several ground squirrels of North America, particularly those formerly classified as Spermophilus* Gopher tortoise , distributed in North America- Other uses :* Minnesota, the...
s, which consume the plants, and feral pigs, which eat the bulbs and trample the habitat. Camatta Canyon amole occurs in an area used by off-road vehicle
Off-road vehicle
An off-road vehicle is considered to be any type of vehicle which is capable of driving on and off paved or gravel surface. It is generally characterized by having large tires with deep, open treads, a flexible suspension, or even caterpillar tracks...
enthusiasts and herds of grazing cattle; these two forces tend to damage cryptogamic soil crusts and encourage the invasion of non-native plants
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
. Invasive plants are a main threat to both varieties, as they outcompete
Competition (biology)
Competition is an interaction between organisms or species, in which the fitness of one is lowered by the presence of another. Limited supply of at least one resource used by both is required. Competition both within and between species is an important topic in ecology, especially community ecology...
them and change the local fire regime
Fire regime
A fire regime is the pattern, frequency and intensity of the bushfires and wildfires that prevails in an area. It is an integral part of fire ecology, and renewal for certain types of ecosystems. If fires are too frequent, plants may be killed before they have matured, or before they have set...
; the Camatta Canyon amole occurs in a single clumped, localized population that could be reduced significantly in a wildfire
Wildfire
A wildfire is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Other names such as brush fire, bushfire, forest fire, desert fire, grass fire, hill fire, squirrel fire, vegetation fire, veldfire, and wilkjjofire may be used to describe the same...
. Other suggested threats to the species include military activities and road maintenance.