Dudleya Variegata
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''Dudleya variegata'' is a
deciduous In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...
succulent plant In botany, succulent plants, also known as succulents, are plants with parts that are thickened, fleshy, and engorged, usually to retain water in arid climates or soil conditions. The word ''succulent'' comes from the Latin word ''sucus'', meanin ...
in the family
Crassulaceae The Crassulaceae (, from Latin ''crassus'', thick), also known as the crassulas, the stonecrops or the orpine family, are a diverse Family (biology), family of dicotyledon angiosperms primarily characterized by succulent leaves and a form of phot ...
known by the common names variegated liveforever, variegated dudleya or rarely San Diego Hasseanthus. A cryptic plant that survives part of the year dormant underground from starch reserves in a
corm Corm, bulbo-tuber, or bulbotuber is a short, vertical, swollen, underground plant stem that serves as a storage organ that some plants use to survive winter or other adverse conditions such as summer drought and heat (perennation). The word ''c ...
, after sufficient rainfall, leaves will emerge, soon giving way to small inflorescences with yellow star-shaped flowers. It is native to
Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...
and adjacent
San Diego County San Diego County (), officially the County of San Diego, is a county in the southwest corner of the U.S. state of California, north to its border with Mexico. As of the 2020 census, the population was 3,298,634; it is the second-most populous ...
in
California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
, where it grows in several habitat types, including
chaparral Chaparral ( ) is a shrubland plant plant community, community found primarily in California, southern Oregon, and northern Baja California. It is shaped by a Mediterranean climate (mild wet winters and hot dry summers) and infrequent, high-intens ...
and
vernal pool Vernal pools, also called vernal ponds or ephemeral pools, are seasonal pools of water that provide habitat for distinctive plants and animals. They are considered to be a distinctive type of wetland usually devoid of fish, and thus allow the saf ...
s.


Description

Although many members of the genus ''Dudleya'' are
rosette Rosette is the French diminutive of ''rose''. It may refer to: Flower shaped designs * Rosette (award), a mark awarded by an organisation * Rosette (design), a small flower design *hence, various flower-shaped or rotational symmetric forms: ** R ...
-forming plants with
evergreen In botany, an evergreen is a plant which has Leaf, foliage that remains green and functional throughout the year. This contrasts with deciduous plants, which lose their foliage completely during the winter or dry season. Consisting of many diffe ...
leaves, this species belongs to the
subgenus In biology, a subgenus ( subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the ge ...
''Hasseanthus,'' which has diverged into
geophytic A storage organ is a part of a plant specifically modified for storage of energy (generally in the form of carbohydrates) or water. Storage organs often grow underground, where they are better protected from attack by herbivores. Plants that have ...
plants. Species within this subgenus are characterized by small, globose and
deciduous In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...
leaves similar in appearance and size to the juvenile leaves of plants outside of the subgenus. The stem has evolved into a
corm Corm, bulbo-tuber, or bulbotuber is a short, vertical, swollen, underground plant stem that serves as a storage organ that some plants use to survive winter or other adverse conditions such as summer drought and heat (perennation). The word ''c ...
-like unit buried under the surface of the soil, and plants utilize
starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diet ...
reserves within the
tuber Tubers are a type of enlarged structure that plants use as storage organs for nutrients, derived from stems or roots. Tubers help plants perennate (survive winter or dry months), provide energy and nutrients, and are a means of asexual reproduc ...
ous root to survive the dry season. The reduced leaves and corm-like caudex are probably
paedomorphic Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny in modern humans is more signi ...
adaptations as most ''Dudleya'' seedlings have a tuberous caudex and small,
drought-deciduous Drought deciduous, or drought semi-deciduous plants refers to plants that shed their leaves during periods of drought or in the dry season. This phenomenon is a natural process of plants and is caused due to the limitation of water around the env ...
leaves. This plant has distinctive, often paddle or spoon-shaped leaves with long petioles. The inflorescences contain spreading bright yellow flowers. The stem is an oblong-shaped corm-like structure. Plants can survive the summer without any water, until moisture returns in mid-October, with the leaves finally re-emerging in November.


Morphology

Plants of this species form 1 to 3 rosettes from the top of the subterranean stem, with each cluster of leaves around wide. The buried stem itself is long, and wide, with a more or less spherical to oblong shape. The leaves are deciduous in summer, and are generally not
glaucous ''Glaucous'' (, ) is used to describe the pale grey or bluish-green appearance of the surfaces of some plants, as well as in the names of birds, such as the glaucous gull (''Larus hyperboreus''), glaucous-winged gull (''Larus glaucescens''), ...
, with an oblanceolate or spoon
shape A shape is a graphics, graphical representation of an object's form or its external boundary, outline, or external Surface (mathematics), surface. It is distinct from other object properties, such as color, Surface texture, texture, or material ...
. The leaves measure long by , with the base generally wide, the tip of the leaf shaped acute to obtuse. The peduncle is tall and wide, with 2 to 3 simple, ascending branches. The branches are long, and have 3 to 11 flowers. The flowers are suspended on
pedicels In botany, a pedicel is a stem that attaches a single flower to the inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branch ...
long. The
sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 Etymology The term ''sepalum'' ...
s of the flower are long, and shaped deltate-ovate. The
petal Petals are modified leaves that form an inner whorl surrounding the reproductive parts of flowers. They are often brightly coloured or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corol ...
s are long by wide, and shaped elliptic. The petals are bright yellow, and have an acute tip. The fruit is spreading, inheriting the characteristic of the flowers. Plants flower from April to June. Chromosome
number A number is a mathematical object used to count, measure, and label. The most basic examples are the natural numbers 1, 2, 3, 4, and so forth. Numbers can be represented in language with number words. More universally, individual numbers can ...
is 2''n'' = 34 (''n'' = 17).


Taxonomy


Taxonomic history

This species was first named by botanist
Sereno Watson Sereno Watson (December 1, 1826 – March 9, 1892) was an American botanist. Life Watson was born on December 1, 1826, in East Windsor Hill, Connecticut. Graduating from Yale in 1847 in biology, he drifted through various occupations unt ...
as ''Sedum variegatum'' in 1876, based on collections by Daniel Cleveland in
San Diego San Diego ( , ) is a city on the Pacific coast of Southern California, adjacent to the Mexico–United States border. With a population of over 1.4 million, it is the List of United States cities by population, eighth-most populous city in t ...
''.'' In 1903,
Joseph Nelson Rose Joseph Nelson Rose (January 11, 1862 – May 4, 1928) was an American botanist. He was born in Union County, Indiana. His father died serving during the Civil War when Joseph Rose was a young boy. He later graduated from high school in Liberty, ...
and
Nathaniel Lord Britton Nathaniel Lord Britton (1859 – 1934) was an American botanist and taxonomist who co-founded the New York Botanical Garden in the Bronx, New York (state), New York. Early life Britton was born on the 15 of January 1859 at New Dorp, Staten Island ...
revised the North American
Crassulaceae The Crassulaceae (, from Latin ''crassus'', thick), also known as the crassulas, the stonecrops or the orpine family, are a diverse Family (biology), family of dicotyledon angiosperms primarily characterized by succulent leaves and a form of phot ...
, and placed this taxon as the
type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...
of a new genus, ''Hasseanthus'', and renamed it ''Hasseanthus variegatus''. In 1945, it was believed that '' Dudleya multicaulis'', at the time called ''Hasseanthus elongatus'', occurred in the Sweetwater River Canyon, at
Dehesa A ''dehesa'' () is a multifunctional, agrosylvopastoral system (a type of agroforestry) and cultural landscape of southern and central Spain and southern Portugal; in Portugal, it is known as a ''montado''. Its name comes from the Latin ''defe ...
,
San Diego County San Diego County (), officially the County of San Diego, is a county in the southwest corner of the U.S. state of California, north to its border with Mexico. As of the 2020 census, the population was 3,298,634; it is the second-most populous ...
. Botanist
Reid Moran Reid Venable Moran (June 30, 1916 – January 21, 2010) was an American botanist and the curator of botany at the San Diego Natural History Museum from 1957 to 1982. Moran was the world authority on the Crassulaceae, a family of succulent plants, ...
studied the population and found that, although containing some morphological differences, they were more well-suited to be ''Hasseanthus variegatus''. Plants at this location flower three to four weeks later than typical ''D. variegata'' populations elsewhere, and also differ in their greater size and yellower foliage. In 1953, Reid Moran transferred the genus ''Hasseanthus'' as a
subgenus In biology, a subgenus ( subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the ge ...
of ''Dudleya'' on the basis of cytotaxonomic work with Dr. Charles H. Uhl, thus creating the current name. In the southern part of its range, particularly near
Rosarito Beach Rosarito is a coastal city in Playas de Rosarito Municipality, Baja California, on the Pacific Coast of Mexico. As of 2010, the city had a population of 65,278. Located south of the US–Mexico border, Rosarito is a part of the greater San Diego ...
and Rancho Cuevas in the north of Baja California, plants similar to this species are found that also combine characteristics of ''
Dudleya blochmaniae ''Dudleya blochmaniae'' is a summer-deciduous succulent plant known by the common names Blochman's liveforever or Blochman's dudleya. This species of ''Dudleya'' survives part of the year with no aboveground presence, surviving as underground cor ...
''. They have relatively thick rosette leaves and a habitat closer to ''D. blochmaniae'', but present with yellow odorless flowers.


Phylogeny

''Dudleya variegata'' is usually grouped into the subgenus ''Hasseanthus'', a taxonomic rank characterized by diminutive size, deciduous leaves and underground
corm Corm, bulbo-tuber, or bulbotuber is a short, vertical, swollen, underground plant stem that serves as a storage organ that some plants use to survive winter or other adverse conditions such as summer drought and heat (perennation). The word ''c ...
s. This would have placed it along with 3 other ''Hasseanthus'' taxa native to San Diego County, ''
Dudleya blochmaniae ''Dudleya blochmaniae'' is a summer-deciduous succulent plant known by the common names Blochman's liveforever or Blochman's dudleya. This species of ''Dudleya'' survives part of the year with no aboveground presence, surviving as underground cor ...
'', ''
Dudleya brevifolia ''Dudleya brevifolia'', is a rare succulent plant known by the common name short-leaved liveforever, short-leaved dudleya or rarely the Del Mar Hasseanthus. It is an edaphic Endemism, endemic that only grows on Lindavista formation Raised beach, ...
'', and '' Dudleya multicaulis''. A phylogenetic study from 2013 suggests that the subgenus ''Hasseanthus'' is not well-supported by molecular analysis, instead tentatively placing this in a clade which includes the majority of ''Hasseanthus'' albeit with the exception of '' D. multicaulis'' and the inclusion of '' D. verityi''.


Hybrids

This species is known to hybridize with other members of the genus. These include: * ''×'' ''Dudleya attenuata'' subsp. ''attenuata'' – Found in extreme north-western Baja California near
Tijuana Tijuana is the most populous city of the Mexican state of Baja California, located on the northwestern Pacific Coast of Mexico. Tijuana is the municipal seat of the Tijuana Municipality, the hub of the Tijuana metropolitan area and the most popu ...
.'''' * ''×'' ''
Dudleya brevifolia ''Dudleya brevifolia'', is a rare succulent plant known by the common name short-leaved liveforever, short-leaved dudleya or rarely the Del Mar Hasseanthus. It is an edaphic Endemism, endemic that only grows on Lindavista formation Raised beach, ...
'' – Hybrids possess intermediate traits, like cream colored flowers. Only identified in the 1970s. Occurred north of Eastgate Mall road in
La Jolla La Jolla ( , ) is a hilly, seaside neighborhood in San Diego, California, occupying of curving coastline along the Pacific Ocean. The population reported in the 2010 census was 46,781. The climate is mild, with an average daily temperature o ...
and the Sorrento Valley.


Distribution and habitat

The plant is endemic to an area roughly 80 km long, from San Diego County down into northwestern Baja California, from Tijuana to
Ensenada Ensenada ("inlet") is a city in Ensenada Municipality, Baja California, situated on the Pacific Coast of Mexico. Located on Bahía de Todos Santos, the city had a population of 279,765 in 2018, making it the third-largest city in Baja Californ ...
. It occurs in relatively small, disjunct populations from near Black Mountain Ranch in San Diego County to Ensenada. Localities in San Diego County that have or had populations include Black Mountain, Kearney Mesa, Dictionary Hill,
San Miguel Mountain San Miguel Mountain is a mountain in Chula Vista, California. It is 2,567' high, and is the 84th highest peak in San Diego County. Because San Miguel is "the highest point close in to the San Diego San Diego ( , ) is a city on the Pacif ...
,
El Cajon El Cajon ( , ; Spanish: El Cajón, lit. 'the box') is a city in San Diego County, California, United States, east of downtown San Diego. The city takes its name from Rancho El Cajón, which was named for the box-like shape of the valley tha ...
, La Mesa, Fletcher Hills, Paradise Hills, Rice Canyon, Dehesa,
Otay Mountain Otay Mountain is a mountain in San Diego County, California. It is the highest summit of the San Ysidro Mountains. The mountain is located in the Otay Mountain Wilderness area. The Mexico-United States border runs along the south face of th ...
,
Imperial Beach Imperial Beach is a beach city in San Diego County, California, United States, with a population of 26,137 as of the 2020 census. It is in the South Bay area of San Diego County, south of downtown San Diego and northwest of downtown Tiju ...
, and the border near the Otay Crossing. There is also an occurrence at the
Silver Strand Training Complex Silver Strand Training Complex (SSTC) is a training facility for U.S. Special Operations Forces. Located between Imperial Beach, California, and Silver Strand State Beach near San Diego. The area is part of Naval Base Coronado and commanded by th ...
, between
Imperial Beach Imperial Beach is a beach city in San Diego County, California, United States, with a population of 26,137 as of the 2020 census. It is in the South Bay area of San Diego County, south of downtown San Diego and northwest of downtown Tiju ...
and Silver Strand State Beach. This species is found typically on dry hillsides and mesas, in foothills and coastal regions usually below . It can be found in the open clearings of
chamise ''Adenostoma fasciculatum'', commonly known as chamise or greasewood, is a flowering plant native to California and Baja California. This shrub is one of the most widespread plants of the California chaparral ecoregion. Chamise produces a specia ...
, sage scrub or
scrub oak Scrub oak is a common name for several species of small, shrubby oaks. It may refer to: *the Chaparral plant community in California, or to one of the following species. In California *California scrub oak ('' Quercus berberidifolia''), a widesp ...
brush, on clay lenses and
vernal pool Vernal pools, also called vernal ponds or ephemeral pools, are seasonal pools of water that provide habitat for distinctive plants and animals. They are considered to be a distinctive type of wetland usually devoid of fish, and thus allow the saf ...
s. Associates include '' Ferocactus viridescens'', '' Selaginella cinerascens'', and '' Selaginella bigelovii''.


Conservation

Severe reversals in the population of the variegated dudleya have been the result of continued urban expansion in the United States and Mexico. The rush to develop
industrial park An industrial park, also known as industrial estate or trading estate, is an area zoned and planned for the purpose of industrial development. An industrial park can be thought of as a more heavyweight version of a business park or office par ...
s and
suburb A suburb (more broadly suburban area) is an area within a metropolitan area. They are oftentimes where most of a metropolitan areas jobs are located with some being predominantly residential. They can either be denser or less densely populated ...
s along the Mexican-American border near
Otay Mesa Otay Mesa ( ) is a community in the southern exclave of San Diego, California, just north of the U.S.–Mexico border. It is bordered by the Otay River Valley and the city of Chula Vista on the north; Interstate 805 and the neighborhoods o ...
has led to extensive devastation of major populations and colonies of the plant. Federal tax benefits for these industrial parks encouraged widespread grading on the mesa, eliminating populations of the inconspicuous plant. Recreational activity is also detrimental to the species.CNPS, Rare Plant Program. 2016. Inventory of Rare and Endangered Plants (online edition, v8-02). California Native Plant Society, Sacramento, CA

/ref>Martin, J. 2005. “Variegated Dudleya ( Dudleya Variegata ) on San Diego National Wildlife Refuge.” San Diego, CA.


See also

* '' Dudleya multicaulis'' – another deciduous ''
Dudleya ''Dudleya'', commonly known as liveforevers, is a genus of rosette-forming succulent plants in the stonecrop family, Crassulaceae, consisting of about 68 taxa in southwestern North America and Guadalupe Island. The species come in many forms, so ...
'' with yellow flowers * '' Hooveria parviflora'' – another bulbous plant that is native to the same ecoregion *
Reid Moran Reid Venable Moran (June 30, 1916 – January 21, 2010) was an American botanist and the curator of botany at the San Diego Natural History Museum from 1957 to 1982. Moran was the world authority on the Crassulaceae, a family of succulent plants, ...


References


External links


Jepson Manual Treatment – ''Dudleya variegata''USDA Plants Profile: Dudleya variegata''Dudleya variegata'' – Photo gallery
{{Taxonbar, from=Q5312066 variegata Flora of California Flora of Baja California Natural history of the California chaparral and woodlands Natural history of San Diego County, California Taxa named by Reid Venable Moran Taxa named by Sereno Watson