Dudleya stolonifera
Encyclopedia
Dudleya stolonifera is a succulent plant
known by the common name Laguna Beach liveforever. This is a rare plant which is endemic to the coastline of Orange County, California
. It is known from only about six populations in the vicinity of Laguna Beach
, totalling about 30,000 individuals. It is federally listed as a threatened species of the United States.
grows from an unbranched caudex
stem and is unusual among related plants in that it has stolon
s from which it sprouts vegetatively. Dudleya stolonifera produces a small rosette of pointed reddish-green leaves and erects a short stem topped with an inflorescence
. The flowers are bright yellow.
cliffs, mostly in coastal sage scrub
habitat, and sometimes in chaparral
. The cliffs are so steep they may be vertical or overhanging. It grows in very thin soils that support very few types of plants; the dudleya is usually found among only moss
es and lichen
s, and sometimes the fern California polypody
(Polypodium californicum). It may have an association with the lichen Niebla ceruchoides, which might act as a bed for the seeds of the dudleya when they fall to the ground.
This species sometimes hybridizes with Dudleya edulis
in the one area where they occur together. Less often it hybridizes with Dudleya lanceolata
.
. When the plant was listed as threatened it was plucked from the wild by plant collectors; this is no longer thought to be a serious problem because the occurrences are too difficult for people to access. Grazing
and trampling by livestock
had a negative effect on the plant but grazing has been stopped in the area, causing the plant to rebound. Climate change
is considered a threat today. Because the populations are few and small the plant may be extirpated
by any major local event, such as wildfire
, or by processes such as inbreeding depression
.
Competition
with other plants, especially non-native
species, threatens the dudleya. In one area it is being displaced by invading
Aeonium haworthii
.
Succulent plant
Succulent plants, also known as succulents or fat plants, are water-retaining plants adapted to arid climates or soil conditions. Succulent plants store water in their leaves, stems, and also in roots...
known by the common name Laguna Beach liveforever. This is a rare plant which is endemic to the coastline of Orange County, California
Orange County, California
Orange County is a county in the U.S. state of California. Its county seat is Santa Ana. As of the 2010 census, its population was 3,010,232, up from 2,846,293 at the 2000 census, making it the third most populous county in California, behind Los Angeles County and San Diego County...
. It is known from only about six populations in the vicinity of Laguna Beach
Laguna Beach, California
Laguna Beach is a seaside resort city and artist community located in southern Orange County, California, United States, approximately southwest of the county seat of Santa Ana...
, totalling about 30,000 individuals. It is federally listed as a threatened species of the United States.
Description
This dudleyaDudleya
Dudleya is a genus of succulent perennials, consisting of about 45 species in southwest North America.Many plants in the Dudleya genus were formerly classified as Echeveria....
grows from an unbranched caudex
Caudex
A caudex is a form of stem morphology appearing as a thickened, short, perennial stem that is either underground or near ground level . It may be swollen for the purpose of water storage, especially in xerophytes...
stem and is unusual among related plants in that it has stolon
Stolon
In biology, stolons are horizontal connections between organisms. They may be part of the organism, or of its skeleton; typically, animal stolons are external skeletons.-In botany:...
s from which it sprouts vegetatively. Dudleya stolonifera produces a small rosette of pointed reddish-green leaves and erects a short stem topped with an inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
. The flowers are bright yellow.
Ecology
This dudleya grows on steep, weathered sandstoneSandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
cliffs, mostly in coastal sage scrub
Coastal sage scrub
Coastal sage scrub is a low scrubland plant community found in the California chaparral and woodlands ecoregion of coastal California and northern Baja California. It is characterized by low-growing aromatic, and drought-deciduous shrubs adapted to the semi-arid Mediterranean climate of the...
habitat, and sometimes in chaparral
Chaparral
Chaparral is a shrubland or heathland plant community found primarily in the U.S. state of California and in the northern portion of the Baja California peninsula, Mexico...
. The cliffs are so steep they may be vertical or overhanging. It grows in very thin soils that support very few types of plants; the dudleya is usually found among only moss
Moss
Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
es and lichen
Lichen
Lichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...
s, and sometimes the fern California polypody
Polypodium californicum
Polypodium californicum is a species of fern known by the common name California polypody. It is native to Baja California and California, where it grows along the coastline as well as in moist spots in coastal foothills and mountain ranges in the southern part of its distribution. This polypody...
(Polypodium californicum). It may have an association with the lichen Niebla ceruchoides, which might act as a bed for the seeds of the dudleya when they fall to the ground.
This species sometimes hybridizes with Dudleya edulis
Dudleya edulis
Dudleya edulis is a succulent plant known by the common name fingertips. This plant is native to Southern California and Baja California, where it grows in rocky areas of the coastal and the inland Peninsular Ranges mountains.-Description:...
in the one area where they occur together. Less often it hybridizes with Dudleya lanceolata
Dudleya lanceolata
Dudleya lanceolata is a succulent plant known by the common name lanceleaf liveforever. This plant is native to the mountains of Southern California and Baja California, where it is found in rocky areas and slopes.-Description:...
.
Conservation
This rare plant faces a number of threats to its survival. The effects of urban development may harm the plant. The habitat is too rugged in most areas to be directly developed, but associated changes to the habitat from nearby development may include the edge effectEdge effect
The edge effect in ecology is the effect of the juxtaposition or placing side by side of contrasting environments on an ecosystem.This term is commonly used in conjunction with the boundary between natural habitats, especially forests, and disturbed or developed land. Edge effects are especially...
. When the plant was listed as threatened it was plucked from the wild by plant collectors; this is no longer thought to be a serious problem because the occurrences are too difficult for people to access. Grazing
Grazing
Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
and trampling by livestock
Livestock
Livestock refers to one or more domesticated animals raised in an agricultural setting to produce commodities such as food, fiber and labor. The term "livestock" as used in this article does not include poultry or farmed fish; however the inclusion of these, especially poultry, within the meaning...
had a negative effect on the plant but grazing has been stopped in the area, causing the plant to rebound. Climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
is considered a threat today. Because the populations are few and small the plant may be extirpated
Local extinction
Local extinction, also known as extirpation, is the condition of a species which ceases to exist in the chosen geographic area of study, though it still exists elsewhere...
by any major local event, such as 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...
, or by processes such as inbreeding depression
Inbreeding depression
Inbreeding depression is the reduced fitness in a given population as a result of breeding of related individuals. It is often the result of a population bottleneck...
.
Competition
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...
with other plants, especially non-native
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...
species, threatens the dudleya. In one area it is being displaced by invading
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
Aeonium haworthii
Aeonium haworthii
Aeonium haworthii is a species of the stonecrop genus Aeonium which is known by the common names Haworth's aeonium and pinwheel. This stonecrop is native to the Canary Islands, but it has been introduced to other areas of similar climate, such as Southern California in the United States. It is also...
.
See also
- California coastal sage and chaparralCalifornia coastal sage and chaparral ecoregionThe California coastal sage and chaparral, a sub-ecoregion of the California chaparral and woodlands ecoregion, is found in southwestern California and northwestern Baja California in Mexico.-Location:...
- (subecoregion)