Dudleya Saxosa Subsp
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''Dudleya'', commonly known as liveforevers ( Spanish: ''siemprevivas'') is a
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
succulent 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'', meani ...
plants in the stonecrop family, Crassulaceae, consisting of about 68 taxa in southwestern
North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
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, which ...
, others
cryptic Cryptic may refer to: In science: * Cryptic species complex, a group of species that are very difficult to distinguish from one another * Crypsis, the ability of animals to blend in to avoid observation * Cryptic era, earliest period of the Earth ...
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, aft ...
, 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 Tubular may refer to: *having the form of a hollow cylinder, or tube *having the form of a cylinder *''Tubular'', a television-related entertainment blog on the ''Houston Chronicle'' website *''Tubular'', a level in the video game ''Super Mario Wor ...
, 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.'' 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'' and ''Cotyledon'', while the cryptic species were placed as ''Sedum''. Taxonomic efforts started by Joseph Nelson Rose 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 (state), New York. Early life Britton was born in New Dorp, Staten Island, New ...
created three genera, which were all eventually subsumed into the ''Dudleya'' proper following
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 plant ...
'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 inva ...
. ''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 i ...
s. In the wild, many species of ''Dudleya'' are vulnerable, as
land development Land development is the alteration of landscape in any number of ways such as: * Changing landforms from a natural or semi-natural state for a purpose such as agriculture or housing * Subdividing real estate into lots, typically for the purpose ...
and poachers 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 geographical and ethno-cultural terms. The modern states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. China, North Korea, South Korea and ...
, especially
South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is formed ...
.
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 a ...
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 Sympodial growth is a bifurcating branching pattern where one branch develops more strongly than the other, resulting in the stronger branches forming the primary shoot and the weaker branches appearing laterally. A sympodium, also referred to a ...
. 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, 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 in 1803, which would later be known as ''
Dudleya caespitosa ''Dudleya caespitosa'' is a succulent plant known by several common names, including sea lettuce, sand lettuce, and coast dudleya. It is endemic to California, where it grows along the coastline in the southern half of the state. Taxonomically, ...
.'' 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 Empire, Austrian scientist who studied medicine, chemistry, zoolog ...
in 1811, and in 1840
Thomas Nuttall Thomas Nuttall (5 January 1786 – 10 September 1859) was an England, English botany, botanist and zoologist who lived and worked in America from 1808 until 1841. Nuttall was born in the village of Long Preston, near Settle, North Yorkshire, S ...
described both ''Echeveria pulverulenta'' (''
Dudleya pulverulenta ''Dudleya pulverulenta'' is a species of 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 greatly contrast with i ...
'') and ''Echeveria lanceolata'' (''
Dudleya lanceolata ''Dudleya lanceolata'' is a succulent plant known by the common name lanceleaf liveforever or lance-leaved dudleya. It is an extremely variable and widely ranging species that occurs from Monterey County and Kern County in California south throug ...
''). 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 (state), New York. Early life Britton was born in New Dorp, Staten Island, New ...
and Joseph Nelson Rose's revision of the North American Crassulaceae 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 Alwin Berger (28 August 1871 – 20 April 1931) was a German botanist best known for his contribution to the nomenclature of succulent plants, particularly agaves and cacti. Born in Germany he worked at the botanical gardens in Dresden and Fran ...
revised the status of ''Dudleya'' and ''Stylophyllum'' into a sectional ranking within '' Echeveria'', while merging the ''Hasseanthus'' genera into '' Sedum''. 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 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 plant ...
, 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 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 Pseudoscience consists of statements, beliefs, or practices that claim to be both scientific and factual but are incompatible with the scientific method. Pseudoscience is often characterized by contradictory, exaggerated or unfalsifiable claim ...
material, including references to the lost continents of Atlantis,
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 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 and the scientifically accepted
age of the Earth The age of Earth is estimated to be 4.54 ± 0.05 billion years This age may represent the age of Earth's accretion, or core formation, or of the material from which Earth formed. This dating is based on evidence from radiometric age-dating of ...
. 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 ''Sedum moraniii'' is a rare species of flowering plant in the family Crassulaceae known by the common name Rogue River stonecrop. It is Endemism, endemic to Oregon in the United States, where it only grows in Josephine County, Oregon, Josephine ...
''. 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 Br ...
'', 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'' 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'' – Vizcaino liveforever *'' Dudleya albiflora''– White-flower liveforever *'' Dudleya anomala'' – Todos Santos liveforever *'' Dudleya anthonyi'' – Anthony's liveforever *'' Dudleya attenuata'' – Orcutt's liveforever, tapertip liveforever *''
Dudleya arizonica ''Dudleya arizonica'' is a species of perennial succulent plant commonly known as the Arizona chalk dudleya and the Arizona liveforever. A member of the genus ''Dudleya'', this species is characterized by long, red flowers that adorn a waxy roset ...
'' – Arizona chalk dudleya. Formerly a subspecies of ''Dudleya pulverulenta''. *'' Dudleya blochmaniae'' – Blochman's liveforever, Blochman's dudleya *'' Dudleya brevifolia'' – 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 ''Dudleya caespitosa'' is a succulent plant known by several common names, including sea lettuce, sand lettuce, and coast dudleya. It is endemic to California, where it grows along the coastline in the southern half of the state. Taxonomically, ...
'' – 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 ''Dudleya cultrata'' is a species of perennial succulent in the family Crassulaceae commonly known as the knife-leaved liveforever or the maritime succulent liveforever. This species is characterized by oblong, narrow green leaves and flowers wi ...
'' – 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 ''Dudleya densiflora'' is a species of succulent plant in the family Crassulaceae known commonly as the San Gabriel Mountains liveforever or San Gabriel Mountains dudleya. A very rare plant confined to the San Gabriel Mountains of Los Angeles ...
'' – 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 ''Dudleya farinosa'' is a species of succulent plant in the family Crassulaceae known by several common names, including bluff lettuce, powdery liveforever, and powdery dudleya. A coastal plant of northern California and southern Oregon, it is typi ...
'' – 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'' – Gates' liveforever *''
Dudleya gnoma ''Dudleya gnoma'' is a rare species of succulent plant in the Crassulaceae, stonecrop family known by the common names munchkin liveforever and munchkin dudleya. It is characterized by its diminutive stature, small yellow flowers, and distinctive ...
'' – 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 ''Dudleya guadalupensis'' is a very rare species of succulent perennial plant in the family Crassulaceae commonly known as the Guadalupe liveforever. It is a rosette-forming leaf succulent, with foliage that is variously colored light green, gree ...
'' – Guadalupe liveforever *'' Dudleya ingens'' – Baja liveforever, rock liveforever *'' Dudleya hendrixii'' – Hendrix's liveforever *''
Dudleya lanceolata ''Dudleya lanceolata'' is a succulent plant known by the common name lanceleaf liveforever or lance-leaved dudleya. It is an extremely variable and widely ranging species that occurs from Monterey County and Kern County in California south throug ...
'' – Lanceleaf liveforever. *''
Dudleya linearis ''Dudleya linearis'' is an insular succulent plant known by common name as the San Benitos Liveforever. It is endemic to the San Benito Islands, a small group of Mexican islands in the Pacific Ocean, west of Cedros Island. The population was alm ...
'' – San Benito Island liveforever *''
Dudleya multicaulis ''Dudleya multicaulis'' is a succulent plant known by the common name manystem liveforever or many-stemmed dudleya. This ''Dudleya'' is endemic to southern California, where it is rare and seriously threatened as its habitat is altered by humans ...
'' – Many-stemmed dudleya *'' Dudleya nubigena'' – Cape liveforever *'' Dudleya nesiotica'' – Santa Cruz Island liveforever *''
Dudleya pachyphytum ''Dudleya pachyphytum'' is an insular succulent plant known by the common name Cedros Island liveforever. It is a member of the genus ''Dudleya,'' in the family Crassulaceae. Characterized by thick, blunt leaves covered in a white, powdery wax ...
'' – Cedros Island dudleya *'' Dudleya palmeri'' – Palmer's liveforever *'' Dudleya parva'' – Conejo dudleya *'' Dudleya pauciflora''– Few-flower liveforever *''
Dudleya pulverulenta ''Dudleya pulverulenta'' is a species of 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 greatly contrast with i ...
'' – 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'' – Panamint liveforever ** ''Dudleya saxosa'' subsp. ''collomiae'' – Gila County liveforever ** ''Dudleya saxosa'' subsp. ''aloides'' – Desert liveforever ** ''Dudleya saxosa'' subsp. ''saxosa'' – Panamint liveforever *'' Dudleya stolonifera'' – 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'' – Variegated liveforever *''
Dudleya verityi ''Dudleya verityi'' is a rare species of succulent plant known by the common name Verity's liveforever. It is endemic to Ventura County, California, where it is known from only three occurrences in the vicinity of Conejo Mountain between Camarill ...
'' – 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 ''Dudleya viscida'' is a rare succulent plant known by common name as the sticky liveforever, sticky dudleya or the San Juan stylophyllum. It is endemic to California, where it is found on rocky slopes. It is unique among the genus ''Dudleya'' in ...
'' – Sticky dudleya


Etymology

The genus is named after
William Russel Dudley William Russel Dudley (March 1, 1849 – June 4, 1911) was an American botanist.Makers of American Botany, Harry Baker Humphrey, Ronald Press Company, Library of Congress Card Number 61-18435 He headed the botany department at Stanford University ...
, the first head of the botany department at
Stanford University Stanford University, officially Leland Stanford Junior University, is a private research university in Stanford, California. The campus occupies , among the largest in the United States, and enrolls over 17,000 students. Stanford is consider ...
. 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: 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
hummingbird Hummingbirds are birds native to the Americas and comprise the biological family Trochilidae. With about 361 species and 113 genera, they occur from Alaska to Tierra del Fuego, but the vast majority of the species are found in the tropics aro ...
s and
bee Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyly, monophyletic lineage within the ...
s, 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 complexes. The flowers are mostly hermaphroditic, 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 stat ...
,
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 Sonora (), officially Estado Libre y Soberano de Sonora ( en, Free and Sovereign State of Sonora), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is d ...
and
Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...
, 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 U.S. state, state in the Western United States, 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. N ...
.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 area, 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 po ...
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.
Mealybug Mealybugs are insects in the family (biology), family Pseudococcidae, unarmored scale insects found in moist, warm habitats. Many species are considered pest (animal), pests as they feed on plant juices of greenhouse plants, house plants and sub ...
s and aphids are main pests of ''Dudleya''. Powdery mildew 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 Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, fer ...
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 vol ...
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 wea ...
, 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 buds 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 Combustibility and flammability, combustible vegetation. Depending on the type of vegetation present, a wildfire ...
, 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'', 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 The Kumeyaay, also known as Tipai-Ipai or by their historical Spanish name Diegueño, is a tribe of Indigenous peoples of the Americas who live at the northern border of Baja California in Mexico and the southern border of California in the Unit ...
and Paipai region utilized the genus for both medicinal and
agricultural Agriculture or farming is the practice of cultivating Plant, plants and livestock. Agriculture was the key development in the rise of Sedentism, sedentary human civilization, whereby farming of Domestication, domesticated species created food ...
purposes. The tender,
succulent 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'', meani ...
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 calluses and corns. The budding
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. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...
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 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 and Mexico, and anthropogenic-induced wildfires. However, one of the most critical threats to ''Dudleya'' species is poaching, partially caused by a demand from
East Asia East Asia is the eastern region of Asia, which is defined in both geographical and ethno-cultural terms. The modern states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. China, North Korea, South Korea and ...
n
succulent 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'', meani ...
collectors Collector(s) may refer to: Arts and entertainment * Collector (character), a fictional character in the Marvel Comics universe * ''Collector'' (2011 film), a 2011 Indian Malayalam film * ''Collector'' (2016 film), a 2016 Russian film * ''Collec ...
paying lucrative prices for certain ''Dudleya'' species.The population of
Verity's liveforever ''Dudleya verityi'' is a rare species of succulent plant known by the common name Verity's liveforever. It is endemic to Ventura County, California, where it is known from only three occurrences in the vicinity of Conejo Mountain between Camari ...
(''Dudleya verityi''), which was nearly wiped out during the 2013
Springs Fire The Springs Fire was a wildfire in Ventura County, California in May 2013. Although the fire burned only 15 homes, it threatened 4,000. This threat passed when rain shower moved through the California area because of a low-pressure system off th ...
, was targeted by poachers. The Cedros Island liveforever (''Dudleya pachyphytum'') is a rare and extremely specialized ''Dudleya'' endemic to Cedros Island. In 2016, Korean nationals began moving to Bahia Tortugas, a locality in
Baja California Sur 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 ...
, 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, or both. In 2020, the Mexican Navy 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 The California Department of Fish and Wildlife (CDFW), formerly known as the California Department of Fish and Game (CDFG), is a state agency under the California Natural Resources Agency. The Department of Fish and Wildlife manages and protect ...
, 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 Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is formed ...
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 va ...
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 Aesthetics, or esthetics, is a branch of philosophy that deals with the nature of beauty and taste, as well as the philosophy of art (its own area of philosophy that comes out of aesthetics). It examines aesthetic values, often expressed th ...
quality of their long
caudices A caudex (plural: caudices) of a plant is a stem, but the term is also used to mean a rootstock and particularly a basal stem structure from which new growth arises.pages 456 and 695 In the strict sense of the term, meaning a stem, "caudex" is ...
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 The California State Assembly is the lower house of the California State Legislature, the upper house being the California State Senate. The Assembly convenes, along with the State Senate, at the California State Capitol in Sacramento. The A ...
member Chris Ward proposed Bil
AB-223
sponsored by the California Native Plant Society, 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'', a genus related to ''Dudleya''. *'' Echeveria'', a genus similar to ''Dudleya''. *
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 plant ...
, 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 (state), New York. Early life Britton was born in New Dorp, Staten Island, New ...
and Joseph Nelson Rose, 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