Dudleya Cymosa 1
   HOME

TheInfoList



OR:

''Dudleya'', commonly known as liveforevers (
Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many Latin American countries **Spanish cuisine Other places * Spanish, Ontario, Can ...
: ''siemprevivas'') is a
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
of succulent plants in the stonecrop family,
Crassulaceae The Crassulaceae (from Latin ''crassus'', thick), also known as the stonecrop family or the orpine family, are a diverse family of dicotyledon flowering plants characterized by succulent leaves and a unique form of photosynthesis, known as Crass ...
, consisting of about 68 taxa in southwestern North America and
Guadalupe Island Guadalupe Island ( es, Isla Guadalupe, link=no) is a volcanic island located off the western coast of Mexico's Baja California Peninsula and about southwest of the city of Ensenada in the state of Baja California, in the Pacific Ocean. The ...
. The species come in multiple divergent forms, some large and
evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, whic ...
, others cryptic 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 leaves, usually in the autumn; to the shedding of petals, ...
, but despite their dramatic variations in appearance, most species readily hybridize. The flowers of ''Dudleya'' have parts numbered in 5, with the petals arranged in tubular, star-shaped, and bell-shaped forms, and when fruiting are filled with tiny, ovoid to crescent-shaped seeds. The genus evolved as neoendemics, from ancestors in the stonecrop genus, ''
Sedum ''Sedum'' is a large genus of flowering plants in the family Crassulaceae, members of which are commonly known as stonecrops. The genus has been described as containing up to 600 species, subsequently reduced to 400–500. They are leaf succul ...
.'' The ancestors radiated southward from ''Sedum'' during the creation of the dry summer climate in the California region 5 million years ago. Early botanists classified the larger species as ''
Echeveria ''Echeveria'' is a large genus of flowering plants in the family Crassulaceae, native to semi-desert areas of Central America, Mexico and northwestern South America. Description Plants may be evergreen or deciduous. Flowers on short stalks (cyme ...
'' and ''Cotyledon'', while the cryptic species were placed as ''Sedum''. Taxonomic efforts started by
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 Libert ...
and
Nathaniel Lord Britton Nathaniel Lord Britton (January 15, 1859 – June 25, 1934) was an American botanist and taxonomist who co-founded the New York Botanical Garden in the Bronx, New York. Early life Britton was born in New Dorp in Staten Island, New York to Jasp ...
created three genera, which were all eventually subsumed into the ''Dudleya'' proper following Reid Moran's investigations into the genus.
Phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
research is still at an early stage in the genus, and is complicated by the fact that many species are becoming
endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and in ...
. ''Dudleya'' is a relatively obscure genus in comparison to other more widely-cultivated succulents, but converging interests by succulent collectors,
native plant In biogeography, a native species is indigenous to a given region or ecosystem if its presence in that region is the result of only local natural evolution (though often popularised as "with no human intervention") during history. The term is equ ...
enthusiasts and gardeners have led to cultivation of many species as
ornamental plant Ornamental plants or garden plants are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars that ...
s. In the wild, many species of ''Dudleya'' are vulnerable, as land development and
poachers Poaching has been defined as the illegal hunting or capturing of wild animals, usually associated with land use rights. Poaching was once performed by impoverished peasants for subsistence purposes and to supplement meager diets. It was set a ...
threaten often
niche Niche may refer to: Science *Developmental niche, a concept for understanding the cultural context of child development *Ecological niche, a term describing the relational position of an organism's species *Niche differentiation, in ecology, the ...
populations of plants. Poached plants are often shipped to
East Asia East Asia is the eastern region of Asia, which is defined in both Geography, geographical and culture, ethno-cultural terms. The modern State (polity), states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. ...
, especially
South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korean Peninsula and sharing a land border with North Korea. Its western border is formed by the Yellow Sea, while its eas ...
.
Conservationists The conservation movement, also known as nature conservation, is a political, environmental, and social movement that seeks to manage and protect natural resources, including animal, fungus, and plant species as well as their habitat for the f ...
, nurseries and
government A government is the system or group of people governing an organized community, generally a state. In the case of its broad associative definition, government normally consists of legislature, executive, and judiciary. Government is ...
s combat ''Dudleya'' poaching through propagation programs and protection laws.


Description


Characteristics and subgenera

This genus is the only taxon of the Sedeae tribe to have evolved sympodial branching. The genus is traditionally divided into three subgenera, two of which were formerly their own genera. The subgenera consist of ''Dudleya, Stylophyllum'', and ''Hasseanthus''.


Epicuticular wax

One of the most famous features of some ''Dudleya'' are their waxy coating. Numerous species have their foliage covered in an
epicuticular wax Epicuticular wax is a coating of wax covering the outer surface of the plant cuticle in land plants. It may form a whitish film or bloom on leaves, fruits and other plant organs. Chemically, it consists of hydrophobic organic compounds, mainly st ...
, or farina. This waxy coating is usually white, chalky, and mealy, and is the namesake in many epithets, like chalk dudleya, powdery liveforever, and giant chalk dudleya. The wax on the giant chalk dudleya is a surface with some of the highest ultraviolet reflectivity ever discovered in plants. When exposed to water, the wax may coat drops on leaves, preventing their evaporation. The farina is mostly composed of pentacyclic
triterpenoids Triterpenes are a class of chemical compounds composed of three terpene units with the molecular formula C30H48; they may also be thought of as consisting of six isoprene units. Animals, plants and fungi all produce triterpenes, including squale ...
. Other members, such as '' D. viscida'' and '' D. anomala'', have a clear, sticky layer on their foliage.Dudleya anomala ''(Davidson) Moran''. Desert Plant Life. 14: 191. 1942. This adhesive layer ultimately helps the plant protect its leaves from the sun, much like ones with "white" wax. It accomplishes this solar protection by allowing dust to adhere to the sticky layer on the leaves, which coats the foliage with dust and debris, blocking solar radiation.


Taxonomy


Taxonomic history


Early history

The earliest species of the genus described was ''Cotyledon caespitosa'', by
Adrian Hardy Haworth Adrian is a form of the Latin given name Adrianus or Hadrianus. Its ultimate origin is most likely via the former river Adria from the Venetic and Illyrian word ''adur'', meaning "sea" or "water". The Adria was until the 8th century BC the mai ...
in 1803, which would later be known as '' Dudleya caespitosa.'' The same species would later be described again as ''Sedum cotyledon'' by
Joseph Franz von Jacquin Joseph "Krystel" Franz Freiherr von Jacquin or Baron Joseph von Jacquin (7 February 1766, in Schemnitz (now Banská Štiavnica) – 26 October 1839, in Vienna) was an Austrian scientist who studied medicine, chemistry, zoology and botany. ...
in 1811, and in 1840
Thomas Nuttall Thomas Nuttall (5 January 1786 – 10 September 1859) was an English botanist and zoologist who lived and worked in America from 1808 until 1841. Nuttall was born in the village of Long Preston, near Settle in the West Riding of Yorkshire and ...
described both ''Echeveria pulverulenta'' (''
Dudleya pulverulenta ''Dudleya pulverulenta'' is a species of Perennial plant, perennial succulent plant known by the common names chalk lettuce, chalk dudleya, and chalk liveforever. It is one of the largest ''Dudleya'', with a silvery, waxy rosette that may greatl ...
'') and ''Echeveria lanceolata'' ('' Dudleya lanceolata''). The differing generic placements of these early descriptions suggest that taxonomic disagreements over the genus had an early start, with some of these generic placements persisting even after the proper description of the genus by Britton and Rose.
Nathaniel Lord Britton Nathaniel Lord Britton (January 15, 1859 – June 25, 1934) was an American botanist and taxonomist who co-founded the New York Botanical Garden in the Bronx, New York. Early life Britton was born in New Dorp in Staten Island, New York to Jasp ...
and
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 Libert ...
's revision of the North American
Crassulaceae The Crassulaceae (from Latin ''crassus'', thick), also known as the stonecrop family or the orpine family, are a diverse family of dicotyledon flowering plants characterized by succulent leaves and a unique form of photosynthesis, known as Crass ...
upended many of the early taxonomic classifications, with the newly-minted genus ''Dudleya'' containing 60 species, of which 41 were newly described by Britton and Rose. The two also defined the related genera ''Stylophyllum'', which contained 12 species, and ''Hasseanthus'', with 4 species. The primary differences between ''Dudleya'' and ''Stylophyllum'' were between the leaf shape, floral structure and petal orientation, whilst ''Hasseanthus'' was characterized by a different vegetative structure and more niche adaptations, primarily corm-like stems and deciduous leaves.Uhl, C. H., & Moran, R. (1953). The cytotaxonomy of Dudleya and Hasseanthus. ''American Journal of Botany'', 492-502. In the 1930s, Alwin Berger revised the status of ''Dudleya'' and ''Stylophyllum'' into a sectional ranking within ''
Echeveria ''Echeveria'' is a large genus of flowering plants in the family Crassulaceae, native to semi-desert areas of Central America, Mexico and northwestern South America. Description Plants may be evergreen or deciduous. Flowers on short stalks (cyme ...
'', while merging the ''Hasseanthus'' genera into ''
Sedum ''Sedum'' is a large genus of flowering plants in the family Crassulaceae, members of which are commonly known as stonecrops. The genus has been described as containing up to 600 species, subsequently reduced to 400–500. They are leaf succul ...
''. This was in part due to a belief that ''Dudleya'' had evolved from ''Echeveria'' radiating northward from Mexico, evidenced by the similar tubular corollas, while ''Hasseanthus'' possessed aesthetic similarities to ''Sedum'', primarily flowers with broadly-spreading petals. ''Stylophyllum'' was believed to occupy a transitory position between ''Dudleya'' and ''Hasseanthus''. These conclusions were widely accepted by botanists for the first half of the 20th century, until proper molecular and phylogenetic analyses began to appear.


Reid Moran, Charles H. Uhl and early phylogenetics

In 1942, Reid Moran, a botanist with a longstanding interest in the genera, offered a new revision of the taxa. Moran recognized ''Dudleya'' as being distinct from ''Echeveria'', and merged ''Stylophyllum'' as a subgenera along with ''Eududleya'' (which was changed to just subgenus ''Dudleya''). Moran still recognized ''Hasseanthus'' as a separate genus, but realized that it was closely related to ''Dudleya''. With assistance from cytologist Charles H. Uhl, Moran came to the conclusion that ''Dudleya'' and ''Hasseanthus'' were related closer to each other than they were to ''Echeveria'' or ''Sedum''. As Moran and Uhl conducted more cytological and taxonomic research on the genus, it became clear that ''Hasseanthus'' was also a subgenera of ''Dudleya'', citing the karyological uniformity and the formation of hybrids between the genera. In contrast, while ''Echeveria'' and ''Sedum'' freely hybridize within themselves and each other, all attempts at hybridizing ''Dudleya'' with ''Echeveria'' have failed. Uhl came to the conclusion that there are probably no intergeneric hybrids with ''Dudleya'', believing that ''Dudleya'' had split from ''Echeveria'' far enough that intergeneric reproductive success was unlikely. Despite Uhl's research, he still believed that ''Dudleya'' had evolved northward from Mexico with ''Echeveria'', probably some time before the formation of the summer-dry climate of California, making ''Dudleya'' a
paleoendemic Paleoendemism along with neoendemism is a possible subcategory of endemism. Paleoendemism refers to species that were formerly widespread but are now restricted to a smaller area. Neoendemism refers to species that have recently arisen, such as thro ...
.


Modern classifications and phylogenetic research

Around 1993, one of the only literary treatments of the genus was written, Paul H. Thomson's ''Dudleya and Hasseanthus Handbook''. In the book, Thompson made numerous changes and adjustments to species, and described several new species. The book included a large number of photographs, extensive descriptions, and horticultural practices for the care of ''Dudleya,'' derived from a long interest growing, visiting and collecting the plants. However, he failed to follow the
International Code of Botanical Nomenclature The ''International Code of Nomenclature for algae, fungi, and plants'' (ICN) is the set of rules and recommendations dealing with the formal botanical names that are given to plants, fungi and a few other groups of organisms, all those "trad ...
guidelines for describing new taxa, forgoing designated
type specimens In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes t ...
, which invalidated his treatment. His treatment also contains extensive pseudoscientific material, including references to the lost continents of
Atlantis Atlantis ( grc, Ἀτλαντὶς νῆσος, , island of Atlas) is a fictional island mentioned in an allegory on the hubris of nations in Plato's works '' Timaeus'' and '' Critias'', wherein it represents the antagonist naval power that b ...
,
Lemuria Lemuria (), or Limuria, was a continent proposed in 1864 by zoologist Philip Sclater, theorized to have sunk beneath the Indian Ocean, later appropriated by occultists in supposed accounts of human origins. The theory was discredited with the di ...
and Mu, a belief that
cosmic ray Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own ...
s and
divine intervention Divine intervention is an event that occurs when a deity (i.e. God or a god) becomes actively involved in changing some situation in human affairs. In contrast to other kinds of divine action, the expression "divine ''intervention''" implies that ...
directly induced the chromosome counts and
evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
of ''Hasseanthus'' and ''Dudleya'', and criticism of
paleontologists Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of foss ...
and the scientifically accepted age of the Earth. Later research challenged the notion that ''Dudleya'' and ''Echeveria'' formed two distinct lineages within Echeverioideae. Joachim Thiede instead proposed that ''Dudleya'' evolved completely independently from ''Echeveria'', evolving from relatives within the ''Leucosedum'' clade like '' Sedum moranii''. This places ''Dudleya'' as a neoendemic that evolved recently with the formation of the summer-dry climate in California. This was evidenced by the similarities of seed-surface ornamentation between ''Dudleya'' and ''Sedum'', which is unlike ''Echeveria'', and the reproductive isolation between ''Echeveria'' and ''Dudleya''.Thiede, J., & Eggli, U. (2007). Crassulaceae. In ''Flowering Plants· Eudicots'' (pp. 83-118). Springer, Berlin, Heidelberg. Chicago Research in the 21st century has supported the hypothesis of ''Dudleya'''s relation to ''Sedum''. Phylogenetic analysis has given weight to this hypothesis, concluding that ''Dudleya'' is much closer to North American members of Sedoideae than to Echeverioideae. The plant ''
Sedum spathulifolium ''Sedum spathulifolium'' is a species of flowering plant in the family Crassulaceae known by the common names broadleaf stonecrop, yellow stonecrop, and spoon-leaved stonecrop. An evergreen perennial, it is native to western North America from B ...
'', which co-exists with ''Dudleya'' in Oregon and California, has been show in multiple phylogenetic reconstructions to be a sister taxon to ''Dudleya'', although it may not be the true sister taxon, as larger samplings are needed. Berger's hypothesis of a relationship between ''Hasseanthus'' and ''Sedum'' may still prove true, as in addition to morphological similarities, the ''Hasseanthus''-type taxa could be basal to the genus. However, no truly conclusive evidence of significant divergence within ''Dudleya'' exists, and it remains unclear which groups are basal or derived.


Selected species

*''
Dudleya abramsii ''Dudleya abramsii'' is a species complex of succulent plants native to California and parts of Baja California. There are numerous subspecies, some critically endangered, with varying habits and lifestyles, but most often characterized by a smal ...
'' ** ''Dudleya abramsii'' subsp. ''abramsii'' – Abrams' liveforever ** ''Dudleya abramsii'' subsp. ''affinis'' – San Bernardino Mountains liveforever ** ''Dudleya abramsii'' subsp. ''bettinae'' – Betty's dudleya ** ''Dudleya abramsii'' subsp. ''calcicola'' – limestone dudleya ** ''Dudleya abramsii'' subsp. ''murina'' – Mouse-gray dudleya ** ''Dudleya abramsii'' subsp. ''setchellii'' – Santa Clara Valley dudleya *''
Dudleya acuminata ''Dudleya acuminata'' is a species of succulent perennial plant in the family Crassulaceae known by common name as the Vizcaino liveforever. A rosette-forming leaf succulent, it has reddish yellow flowers that emerge from April to May. It is nat ...
'' – Vizcaino liveforever *''
Dudleya albiflora ''Dudleya albiflora'', known by the common name white-flower liveforever, is a species of succulent perennial plant in the family Crassulaceae. It is native to the Baja California Peninsula. This species represents numerous populations with var ...
''– White-flower liveforever *'' Dudleya anomala'' – Todos Santos liveforever *'' Dudleya anthonyi'' – Anthony's liveforever *''
Dudleya attenuata ''Dudleya attenuata'' is a species of perennial succulent plant known by the common name taper-tip liveforever, native to Baja California and a small portion of California. A rosette-forming leaf succulent, it has narrow pencil shaped leaves tha ...
'' – Orcutt's liveforever, tapertip liveforever *'' Dudleya arizonica'' – Arizona chalk dudleya. Formerly a subspecies of ''Dudleya pulverulenta''. *''
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 ...
'' – Blochman's liveforever, Blochman's dudleya *''
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 the mesas of the most ancient Raise ...
'' – Short-leaved liveforever, short-leaved dudleya. Formerly a subspecies of ''D. blochmaniae''. *''
Dudleya brittonii ''Dudleya brittonii'', with the common names Britton's dudleya, Britton's liveforever and giant chalk dudleya, is a succulent plant in the family Crassulaceae. It is native to the coast of northern Baja California, Mexico. Both forms of the plan ...
'' – Britton's dudleya, giant chalk dudleya *'' Dudleya caespitosa'' – Coast dudleya, sea lettuce, sand lettuce *'' Dudleya campanulata'' – Punta Banda liveforever *''
Dudleya candelabrum ''Dudleya candelabrum'' is a species of succulent plant known by the common names candleholder liveforever or candleholder dudleya. Endemic to California, this species grows wild only on the northern Channel Islands (California), Channel Islands, ...
'' – Candleholder liveforever *'' Dudleya candida'' – Coronados liveforever *'' Dudleya cedrosensis'' *'' Dudleya crassifolia'' – Thick-leaf dudleyaDodero, M. W. and M. G. Simpson. (2012)
"''Dudleya crassifolia'' (Crassulaceae), a new species from northern Baja California, Mexico"
''Madroño'' 59(4) 223–229.
*'' Dudleya cultrata'' – Knife-leaved liveforever, maritime succulent liveforever *''
Dudleya cymosa ''Dudleya cymosa'' is a species complex of evergreen and deciduous succulent plants in the family Crassulaceae known by the common name: canyon liveforever. It is a loosely defined polyphyletic species with a diverse number of subspecies, varying ...
'' – Canyon liveforever ** ''Dudleya cymosa'' subsp. ''agourensis'' – Agoura Hills dudleya ** ''Dudleya cymosa'' subsp. ''crebrifolia'' – San Gabriel River dudleya ** ''Dudleya cymosa'' subsp. ''costatifolia'' – Pierpoint Springs dudleya ** ''Dudleya cymosa'' subsp. ''cymosa'' – Coast Range dudleya ** ''Dudleya cymosa'' subsp. ''marcescens'' – Marcescent dudleya ** ''Dudleya cymosa.'' subsp. ''ovatifolia'' – Santa Monica Mountains dudleya ** ''Dudleya cymosa'' subsp. ''paniculata'' – Diablo range dudleya ** ''Dudleya cymosa'' subsp. ''pumila'' – Transverse ranges liveforever *'' Dudleya densiflora'' – San Gabriel Mountains liveforever *''
Dudleya edulis ''Dudleya edulis'' is a species of perennial succulent plant known by the common names fingertips, lady fingers, mission lettuce and the San Diego dudleya. The common name denotes the finger-like shape of the leaves, while the specific epithet '' ...
'' – Fingertips, lady fingers, San Diego dudleya *'' Dudleya farinosa'' – Bluff lettuce, powdery liveforever, powdery dudleya *''
Dudleya formosa ''Dudleya formosa'', known by the common name La Misión liveforever, is a species of perennial succulent plant endemic to the Guadalupe Valley in Baja California. It is characterized by bright green leaves, red floral stems, and pink flowers. ...
'' – La Mision liveforever *''
Dudleya gatesii ''Dudleya gatesii'', known by the common name as Gates' liveforever, is a species of perennial succulent plant in the family Crassulaceae. It is native to the central desert of the Baja California peninsula, found growing along dry and rocky outc ...
'' – Gates' liveforever *'' Dudleya gnoma'' – Munchkin dudleya *''
Dudleya greenei ''Dudleya greenei'' is a perennial species of succulent plant known by the common names Greene's liveforever, or Greene's dudleya. It is endemic to the Channel Islands of California, where it grows along the cliffs of four of the eight islands. ...
'' – Greene's dudleya *'' Dudleya guadalupensis'' – Guadalupe liveforever *''
Dudleya ingens ''Dudleya ingens'' is a species of perennial succulent plant in the family Crassulaceae commonly known as the rock liveforever or Baja liveforever. A relatively large member of the genus ''Dudleya'', this species has long green succulent leaves, an ...
'' – Baja liveforever, rock liveforever *'' Dudleya hendrixii'' – Hendrix's liveforever *'' Dudleya lanceolata'' – Lanceleaf liveforever. *'' Dudleya linearis'' – San Benito Island liveforever *'' Dudleya multicaulis'' – Many-stemmed dudleya *'' Dudleya nubigena'' – Cape liveforever *'' Dudleya nesiotica'' – Santa Cruz Island liveforever *'' Dudleya pachyphytum'' – Cedros Island dudleya *''
Dudleya palmeri ''Dudleya palmeri'' is a species of succulent plant in the family Crassulaceae known by the common name Palmer's liveforever. This ''Dudleya'' is endemic to California where it grows along the coast. It is characterized by orange to red over yell ...
'' – Palmer's liveforever *''
Dudleya parva ''Dudleya parva'', known by common name as the Conejo dudleya, is a species of deciduous succulent plant native to the Conejo Valley and surrounding regions. It blooms from May to June, and has vernal leaves. It is only found from the western en ...
'' – Conejo dudleya *'' Dudleya pauciflora''– Few-flower liveforever *''
Dudleya pulverulenta ''Dudleya pulverulenta'' is a species of Perennial plant, perennial succulent plant known by the common names chalk lettuce, chalk dudleya, and chalk liveforever. It is one of the largest ''Dudleya'', with a silvery, waxy rosette that may greatl ...
'' – Chalk lettuce, chalk dudleya, chalk liveforever *'' Dudleya rigida'' – Sierra de la Laguna liveforever *'' Dudleya rigidiflora'' – Playa Maria liveforever *'' Dudleya rubens'' – Red flowering liveforever *''
Dudleya saxosa ''Dudleya saxosa'' is a perennial succulent plant species in the family Crassulaceae, within the genus ''Dudleya'', which are commonly known as ''liveforevers''.Mojave Desert Wildflowers, Pam MacKay, 2nd ed., 2013, This species is a complex of 3 ...
'' – Panamint liveforever ** ''Dudleya saxosa'' subsp. ''collomiae'' – Gila County liveforever ** ''Dudleya saxosa'' subsp. ''aloides'' – Desert liveforever ** ''Dudleya saxosa'' subsp. ''saxosa'' – Panamint liveforever *''
Dudleya stolonifera ''Dudleya stolonifera'' is a succulent plant known by the common name Laguna Beach liveforever or Laguna Beach dudleya. This is a rare plant which is endemic to the coastline of Orange County, California. It is known from only about six populatio ...
'' – Laguna Beach liveforever *''
Dudleya traskiae ''Dudleya traskiae'' (originally spelled ''Dudleya traskae'') is a rare succulent plant known by the common name Santa Barbara Island liveforever. This ''Dudleya'' is endemic to Santa Barbara Island, one of the Channel Islands of California, whe ...
'' – Santa Barbara Island liveforever *''
Dudleya variegata ''Dudleya variegata'' is a deciduous succulent plant in the family Crassulaceae known by the common names variegated liveforever, variegated dudleya or rarely San Diego Hasseanthus. A cryptic plant that survives part of the year dormant undergro ...
'' – Variegated liveforever *'' Dudleya verityi'' – Verity's liveforever *''
Dudleya virens ''Dudleya virens'', the green liveforever or bright green dudleya, is an uncommon species of perennial, succulent plant in the family Crassulaceae, native to several coastal southern California and Baja California locations. Distribution The ...
'' – Alabaster plant, Island liveforever *'' Dudleya viridicata'' – Colonet liveforever *'' Dudleya viridis'' *'' Dudleya viscida'' – Sticky dudleya


Etymology

The genus is named after William Russel Dudley, the first head of the botany department at Stanford University. The term ''liveforever'' may refer to the longevity and hardiness of some plants in the wild. The name of the subgenera ''Stylophyllum'' is an
allusion Allusion is a figure of speech, in which an object or circumstance from unrelated context is referred to covertly or indirectly. It is left to the audience to make the direct connection. Where the connection is directly and explicitly stated (as ...
to the pencil-shaped leaves of the type species, ''Stylophyllum edule'', now known as ''Dudleya edulis''. The name of the subgenera ''Hasseanthus'' was in honor of Dr. Hermann E. Hasse, a surgeon and collector of California flora. ''Dudleya virens'' subsp. ''hassei'' is also named after him.


Nomenclature

*
English English usually refers to: * English language * English people English may also refer to: Peoples, culture, and language * ''English'', an adjective for something of, from, or related to England ** English national ide ...
: ''Dudleya, liveforever'' *
Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many Latin American countries **Spanish cuisine Other places * Spanish, Ontario, Can ...
: s''iempreviva, mezcalito'' * Tiipai: ''milhka’mey'' (wide-leaf); ''milh kajmila'' (narrow-leaf) * Paipai: ''awi mielh''


Reproductive biology


Pollinators and flower morphology

The pollinators of ''Dudleya'' are mostly hummingbirds and bees, although this has been inferred in some species only from flower morphology. The genus exhibits a wide array of diverse flower varieties, even within
species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...
es. The flowers are mostly
hermaphroditic In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many taxonomic groups of animals (mostly invertebrates) do not have s ...
, although some individuals may have sterile anthers. Plants with long, tubular, reddish flowers, mostly in the subgenus ''Dudleya'', are adapted towards pollination via hummingbirds, while short, spreading, yellow flowers favor pollination by insects. Despite the evolution of long flowers towards hummingbirds, the long flowers also show no performance disadvantage in pollination environments exclusively composed of insects. While the long flowers may provide an evolutionary advantage for more effective pollination, more energy is required to produce the larger amounts of floral tissue. The flower morphology of ''Dudleya'' also corresponds with the aforementioned groups of ''Hasseanthus'', ''Stylophyllum'', and ''Dudleya''. The flowers in ''Hasseanthus'' and ''Stylophyllum'' are broad, white to yellow, and spreading, with bumblebees and bees as primary pollinators, and hummingbirds as occasional pollinators. As these species grade towards the subgenus ''Dudleya'', the petals begin to fuse at the base, with the flowers becoming tubular and red, due to an association with hummingbird pollinators. This shift in pollinators corresponds to larger nectar volumes and higher energy contents in accordance with the demands of hummingbird pollinators.


Seeds

Seed morphology also differs between ''Dudleya''. Larger ''Dudleya'' have noticeably smaller seeds; this is likely a result of an evolutionary tradeoff. The investment in growing large allows plants to retain moisture in periods of drought, at the cost of energy placed into reproduction. Other reasons for smaller seeds may also be due to allocation of resources into vegetative reproduction via pup rosettes, instead of sexual reproduction. In contrast, the small, inconspicuous, ''Hasseanthus''-type members produce the largest seeds in the genus. These larger seeds are not distributed very far, which contributes to the restricted ranges of the ''Hasseanthus'' subgenus.Amoroso, D. M., & Wilson, P. (2018). Ten Cases of Divergence in the Seedling Ecology of Dudleya (Crassulaceae). ''Systematic Botany'', ''43''(4), 889-900. File:2017-06-17-14.05.23 ZS PMax Dudleya caespitosa-1 - Flickr - John Rusk.jpg, subg. ' — The flowers of ''Dudleya caespitosa'' File:2017-08-19-13.55.44 ZS PMax Dudleya anthonyi—1—DxO (36281178490).jpg, subg. ' — The flowers of ''Dudleya anthonyi'' File:Dudleyaedulis.jpg, subg. ' — The flowers of ''Dudleya edulis'' File:Dudleya virens hassei.jpg, subg. ' — The flowers of ''Dudleya virens'' subsp. ''hassei'' File:Dudleyablochmaniae.jpg, subg. ' — The flowers of ''Dudleya blochmaniae'' File:Dudleya variegata 186339494.jpg, subg. ' - The flowers of ''Dudleya variegata''


Distribution and habitat

''Dudleya'' species are widespread and diverse in their range, but are typically found in rock outcroppings, cliff faces, or road cuts, where their leaves help them store water in a setting too dry for most types of plants. Most are small and inconspicuous when not in bloom. The two predominant habitats where plants of this genera may be found are by the coast or mountains. Dudleya favor moderate temperatures, summer dormancy, winter precipitation, and rocky habitats, which means they may be found in diverse, disjunct locales from oceanic bluffs on the California coast to sky islands in Arizona. Regions where ''Dudleya'' can be found include
The Californias The Californias ( Spanish: ''Las Californias''), occasionally known as The Three Californias or Two Californias, are a region of North America spanning the United States and Mexico, consisting of the U.S. state of California and the Mexican s ...
,
Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...
, coastal Sonora and
Oregon Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idaho. T ...
, and southern
Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...
and
Nevada Nevada ( ; ) is a state in the Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the 7th-most extensive, ...
.Thiede, J. (2004). The genus Dudleya Britton & Rose (Crassulaceae): its systematics and biology. ''Cactus and Succulent Journal (US)'', ''76'', 224-231. The diversity of species of ''Dudleya'' is centered in
Southern California Southern California (commonly shortened to SoCal) is a geographic and cultural region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most populous urban a ...
and northern
Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...
.


Horticulture


Watering

In horticulture, ''Dudleya'' should be planted at an angle. This allows accumulated water to drain from the nestlike center of the plant, thus preventing microbial decay. ''Dudleya'' should not be watered from directly above, as this may damage their chalky coating known as farina, which is present on numerous species. During the late fall to early spring period of growing, watering should be done frequently in order to promote good growth and flower development. Plants grown with exposure to rainfall, provided they are in a Mediterranean climate, they may obtain optimum moisture. In contrast, plants grown indoors or in greenhouses should be watered to ensure that the plant maximizes growth. During the dormant period, from late spring to fall, watering should be limited to bi-weekly intervals, but not completely cut out. In nature, plants may completely desiccate themselves during the dormant period. Deciduous members of the genus in the ''Hasseanthus'' grouping should not be watered at all during dormancy.


Growing medium

Growing mediums should attempt to imitate the preferred soil of each species in nature. The most essential element for the medium is good drainage. Good drainage is important, as ''Dudleya'' are very susceptible to mold and fungi. How quickly the medium drains should be determined by the amount of shade in the location, which affects the rate of evaporation that the soil will go through. Thus, well-shaded ''Dudleya'' must have excellent drainage. Fertilizers may be used to maintain good color and growth, but they should be diluted. Clay is preferable to plastic pots when growing the plants due to the advantages with water drainage. Plastic pots may also kill the plants by overheating the roots. Mealybugs and
aphid Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white woolly aphids. A t ...
s are main pests of ''Dudleya''.
Powdery mildew Powdery mildew is a fungal disease that affects a wide range of plants. Powdery mildew diseases are caused by many different species of ascomycete fungi in the order Erysiphales. Powdery mildew is one of the easier plant diseases to identify, a ...
has also been recorded in cultivated ''Dudleya''.


Shade

The amount of shade a species of ''Dudleya'' requires is dependent on the location. Plants growing in coastal regions may require little shade at all, whilst plants growing in the deserts, inland valleys and mountains will require shade. The majority of plants in the genus will appreciate north-facing sites and shade during the heat of the day. During the summer months, 50% shade may be beneficial for plants. If a cold-tolerant ''Dudleya'' is grown during a freeze or snow, it should be shaded as not to damage the plant, as a quick thaw may be detrimental.


Propagation

Unlike their related genera ''Echeveria'', many ''Dudleya'' cannot be propagated through leaf cuttings. Propagation is mostly achieved via offsets, germination by seed, or in nurseries, plant tissue culture.


Sexual reproduction

''Dudleya'' seeds are crescent shaped and near-microscopic, and can be collected by taking the dried flower buds and crushing the ovules inside, which can contain hundreds of seeds. Seeds can be sown into a soilless medium, such as
pumice Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicular v ...
or
vermiculite Vermiculite is a hydrous phyllosilicate mineral which undergoes significant expansion when heated. Exfoliation occurs when the mineral is heated sufficiently, and commercial furnaces can routinely produce this effect. Vermiculite forms by the we ...
, after which germination can occur within a week to 10 days.


Asexual reproduction

Vegetative reproduction Vegetative reproduction (also known as vegetative propagation, vegetative multiplication or cloning) is any form of asexual reproduction occurring in plants in which a new plant grows from a fragment or cutting of the parent plant or spec ...
may occur in multiple ways: # The rosette of the plant divides into two, eventually branching off to develop two separate rosettes. # Plantlets will form in the
axillary bud The axillary bud (or lateral bud) is an embryonic or organogenic shoot located in the axil of a leaf. Each bud has the potential to form shoots, and may be specialized in producing either vegetative shoots (stems and branches) or reproductive ...
s of old leaves around the primary rosettes, forming as many as 10 new rosettes. # After a
wildfire A wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identi ...
, when the plant has its main rosettes burned off, new ones will emerge from either the stem or the roots, forming a new plant within a single growing season. # Rosettes emerge out of a long, horizontal root. This is commonplace when the plant has been decapitated on a cliff face, leaving only the long roots, which send out rosettes. # Plants multiply via stoloniferous growth. Many ''Dudleya'' may send out stoloniferous rosettes, but they do not root. Only does the Laguna Beach Liveforever (''Dudleya stolonifera'') sprout roots out of stoloniferous plantlets, yet this can be difficult or impossible to induce in captivity. # When the underground portion of the plant is lost to root rot, but the rosette and part of the caudex survive, the parts above the decayed roots can be removed cleanly, and planted provided they send out roots. Conversely, should the top of the rosette die but the lower stem still live, the deceased portion may be removed, a depression will remain in the caudex where the decayed rosette was removed, and at the edges new buds will sprout. # Propagation via leaves. Only certain species, like those of the ''Hasseanthus'' subgenus and others like ''
Dudleya parva ''Dudleya parva'', known by common name as the Conejo dudleya, is a species of deciduous succulent plant native to the Conejo Valley and surrounding regions. It blooms from May to June, and has vernal leaves. It is only found from the western en ...
'', will root. Most ''Dudleya'' will not reproduce from leaves, with the leaves simply dying after being severed. #
Plant tissue culture Plant tissue culture is a collection of techniques used to maintain or grow plant cells, tissues or organs under sterile conditions on a nutrient culture medium of known composition. It is widely used to produce clones of a plant in a method known ...
methods are also available, and becoming more advanced. Currently, plant tissue culture is used for ''Dudleya'' propagation in commercial and conservation settings.


Ethnobotany


Kumeyaay and Paipai

The indigenous peoples of the Kumeyaay and Paipai region utilized the genus for both
medicinal Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care practic ...
and agricultural purposes. The tender, succulent leaves were chewed on to alleviate
thirst Thirst is the craving for potable fluids, resulting in the basic instinct of animals to drink. It is an essential mechanism involved in fluid balance. It arises from a lack of fluids or an increase in the concentration of certain osmolites, suc ...
, or used to treat
callus A callus is an area of thickened and sometimes hardened skin that forms as a response to repeated friction, pressure, or other irritation. Since repeated contact is required, calluses are most often found on the feet and hands, but they may o ...
es and corns. The budding
inflorescence An inflorescence is a group or cluster of flowers arranged on a Plant stem, stem that is composed of a main branch or a complicated arrangement of branches. Morphology (biology), Morphologically, it is the modified part of the shoot of sperma ...
s, in their early stages, were used as food, with a sweet flavor and juicy texture. The roots were pounded up and soaked in water, used as an
astringent An astringent (sometimes called adstringent) is a chemical that shrinks or constricts body tissues. The word derives from the Latin ''adstringere'', which means "to bind fast". Calamine lotion, witch hazel, and yerba mansa, a Californian pla ...
to "tighten the gums." The roots were also boiled whole as a decoction for asthma.Wilken, Michael A. (2012) ''An Ethnobotany of Baja California's Kumeyaay Indians.'' Retrieved 13 October 2021


Conservation

Several species of ''Dudleya'' are threatened by urban development in
Coastal California Coastal California, also known as the California Coastline and the Golden Coast, refers to the coastal regions of the U.S. state of California. The term is not primarily geographical as it also describes an area distinguished by cultural, economic ...
and Mexico, and anthropogenic-induced wildfires. However, one of the most critical threats to ''Dudleya'' species is
poaching Poaching has been defined as the illegal hunting or capturing of wild animals, usually associated with land use rights. Poaching was once performed by impoverished peasants for subsistence purposes and to supplement meager diets. It was set a ...
, partially caused by a demand from
East Asia East Asia is the eastern region of Asia, which is defined in both Geography, geographical and culture, ethno-cultural terms. The modern State (polity), states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. ...
n succulent collectors paying lucrative prices for certain ''Dudleya'' species.The population of Verity's liveforever (''Dudleya verityi''), which was nearly wiped out during the 2013 Springs Fire, was targeted by poachers. The Cedros Island liveforever (''Dudleya pachyphytum'') is a rare and extremely specialized ''Dudleya'' endemic to
Cedros Island Cedros Island (''Isla de Cedros'', "island of cedars" in Spanish) is an island in the Pacific Ocean belonging to the state of Baja California, Mexico. The dry and rocky island had a population of 1,350 in 2005 and has an area of which include ...
. In 2016, Korean nationals began moving to Bahia Tortugas, a locality in Baja California Sur, to facilitate the poaching and shipping of the plants. The species was seriously threatened after Mexican soldiers discovered poachers taking nearly 5,000 rosettes in a tractor-trailer. It was suspected the poachers rappelled onto the succulent's location via helicopter, as ''D. pachyphytum'' occupies a nearly inaccessible habitat. In 2019, the deaths and injuries of several fishermen from
Bahía Tortugas Baja California Sur (; 'South Lower California'), officially the Free and Sovereign State of Baja California Sur ( es, Estado Libre y Soberano de Baja California Sur), is the least populated state and the 31st admitted state of the 32 federal ent ...
who were on Cedros Island was allegedly the result of ''Dudleya'' trafficking, a conflict with the
Sinaloa Cartel The Sinaloa Cartel ( es, link=no, Cártel de Sinaloa), also known as the CDS, the Guzmán-Loera Organization, the Pacific Cartel, the Federation and the Blood Alliance, is a large, international organized crime syndicate that specializes in il ...
, or both. In 2020, the
Mexican Navy The Mexican Navy is one of the two independent armed forces of Mexico. The actual naval forces are called the ''Armada de México''. The ''Secretaría de Marina'' (''SEMAR'') (English: Naval Secretariat) includes both the ''Armada'' itself and ...
in the Second Naval Region revealed that two fishermen were killed after a dispute emerged over the trafficking of the rare plant. Bluff lettuce (''Dudleya farinosa'') was also targeted by poachers in numerous large-scale operations. Although not particularly rare, the size of the poaching operation pose a serious ecological threat. Starting in 2017, the
U.S. Customs and Border Protection United States Customs and Border Protection (CBP) is the largest federal law enforcement agency of the United States Department of Homeland Security. It is the country's primary border control organization, charged with regulating and facilit ...
, along with the California Department of Fish and Wildlife, discovered large amounts of ''D.'' ''farinosa'' being shipped out of the country.
South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korean Peninsula and sharing a land border with North Korea. Its western border is formed by the Yellow Sea, while its eas ...
n and
Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of ...
nationals have both been arrested in the smuggling of ''D. farinosa.'' According to nursery owners responsible for legally exporting ''Dudleya'', buyers in Asia desired plants directly from the wild, owing to the aesthetic quality of their long caudices and weathered leaves. The candleholder dudleya (''Dudleya candelabrum''), native to the northern
Channel Islands The Channel Islands ( nrf, Îles d'la Manche; french: îles Anglo-Normandes or ''îles de la Manche'') are an archipelago in the English Channel, off the French coast of Normandy. They include two Crown Dependencies: the Bailiwick of Jersey, ...
, was reported to have been poached, with the thieves shipping plants to South Korea. In response to the poaching of ''Dudleya,'' California State Assembly member Chris Ward proposed Bil
AB-223
sponsored by the
California Native Plant Society The California Native Plant Society (CNPS) is a California environmental non-profit organization (501(c)3) that seeks to increase understanding of California's native flora and to preserve it for future generations. The mission of CNPS is to con ...
, which would make it illegal to poach ''Dudleya'' from state or private lands without a permit. The California Native Plant Society and conservationists have also initiated propagation programs to oversaturate the market as a means to deter poachers. On September 28, 2021, governor Gavin Newsom signed AB-223 into law.


See also

*''
Sedum ''Sedum'' is a large genus of flowering plants in the family Crassulaceae, members of which are commonly known as stonecrops. The genus has been described as containing up to 600 species, subsequently reduced to 400–500. They are leaf succul ...
'', a genus related to ''Dudleya''. *''
Echeveria ''Echeveria'' is a large genus of flowering plants in the family Crassulaceae, native to semi-desert areas of Central America, Mexico and northwestern South America. Description Plants may be evergreen or deciduous. Flowers on short stalks (cyme ...
'', a genus similar to ''Dudleya''. * Reid Moran, who contributed greatly to the taxonomy of the genus. *
Nathaniel Lord Britton Nathaniel Lord Britton (January 15, 1859 – June 25, 1934) was an American botanist and taxonomist who co-founded the New York Botanical Garden in the Bronx, New York. Early life Britton was born in New Dorp in Staten Island, New York to Jasp ...
and
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 Libert ...
, who described the genus.


References


Further reading

*Thompson, P. ''Dudleya and Hassenthaus Handbook''. Bonsall Publications. 1993.
Treatment from the Jepson Manual
{{Taxonbar, from1=Q138291, from2=Q87176181, from3=Q15733393 Crassulaceae genera Flora of California Flora of Baja California Succulent plants