Dudleya stolonifera

Last updated

Dudleya stolonifera
Dudleya stolonifera (Laguna Beach liveforever) FWS.jpg
Status TNC G1.svg
Critically Imperiled  (NatureServe) [1]
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Saxifragales
Family: Crassulaceae
Genus: Dudleya
Species:
D. stolonifera
Binomial name
Dudleya stolonifera
Moran

Dudleya stolonifera is a succulent plant known by the common name Laguna Beach liveforever or Laguna Beach dudleya. [1] This is a rare plant which is endemic to the coastline of Orange County, California. It is known from only about six populations in the vicinity of Laguna Beach, totaling about 30,000 individuals. [2] It is federally listed as a threatened species of the United States.

Contents

Description

A robust plant on the left and an average plant on the right, from the type description. Dudleya stolonifera from type description.jpg
A robust plant on the left and an average plant on the right, from the type description.

This Dudleya grows from an unbranched caudex and is unusual among related plants in that it has stolons from which it sprouts vegetatively. Other species of Dudleya only grow solitary or produce dichotomous branches, unless their terminal meristems are damaged. This species produces a small rosette of pointed reddish-green leaves and erects a short peduncle topped with an inflorescence of bright yellow flowers.

Morphology

This species grows one to several rosettes on a caudex, with new rosettes emerging from stolons that grow laterally outwards. The caudex is usually 1.5–3 cm (0.59–1.18 in) wide. Each of the rosettes may be 1–10 cm (0.39–3.94 in) wide, and have 15 to 30 leaves. The leaves are evergreen, not glaucous, and colored a lime-green, tinged maroon on the lower surface. The leaves are shaped oblong-obovate, with the tip short-acuminate to mucronate. The leaf blades measure 3–7 cm (1.2–2.8 in) long, 1.5–3 cm (0.59–1.18 in) wide, and 3–4 mm (0.12–0.16 in) thick, with the base of the leaf 1–2 cm (0.39–0.79 in) wide. [3] [4]

The peduncle is 2–25 cm (0.79–9.84 in) tall, and 1–4 mm (0.039–0.157 in) wide. The peduncle is covered in 15 to 25 spreading bracts, which are shaped cordate-ovate, and are 8–13 mm (0.31–0.51 in) by 5–7 mm (0.20–0.28 in) wide. The inflorescence is an ascending cyme, which is simple or 1 to 2 branched. The branches may subsequently be simply or 1 times bifurcate, and give way to the cincinni, or terminal branches. The terminal branches are circinate, unfurling like a fern's frond, and have 3 to 9 flowers on them. The flowers are suspended on pedicels 5–8 mm (0.20–0.31 in) long. [3] [4]

The inflorescence, from the type description. Dudleya stolonifera flowers from type description.jpg
The inflorescence, from the type description.

The sepals on the flower are 2–3 mm (0.079–0.118 in) long, shaped deltate, and are wider than they are long. The petals are 10–11 mm (0.39–0.43 in) long and 3–3.5 mm (0.12–0.14 in), fused (connate) 1–2 mm (0.039–0.079 in). The petals are shaped elliptic, with outcurved, acute tips, and colored a bright yellow. The pistils are not connivent, and are suberect. The fruit is ascending. [3] [4]

The plant flowers from May to July. [4]

Taxonomy

This species was treated as Echeveria caespitosa ( Dudleya caespitosa ) by Philip A. Munz in his Manual of Southern California Botany. The plants identified as D. caespitosa, which is native to the Central Coast of California, differ greatly from Dudleya stolonifera, as D. caespitosa is dichotomously branching, has an elongate caudex, longer, narrow, and thicker leaves, a larger, taller, and more complex inflorescence, and erect fruits. [5]

Botanist Reid Moran, who specialized in Dudleya, wrote the type description for Dudleya stolonifera in 1949, based on the obvious discrepancy between the plants in Orange County and their assignment to E. caespitosa. He also notes that Munz placed another species, Dudleya ovatifolia, from the Santa Monica Mountains, under Echeveria caespitosa. This species, actually Dudleya cymosa subsp. ovatifolia, shares similar characteristics to D. stolonifera, including the maroon suffusion on the underside of the leaves, the similar size and shape of the leaves, the bright yellow petals, and the short floral stems. Although Moran notes that this resemblance may be only superficial, he states that no other species of Dudleya more closely approaches D. stolonifera. [5]

Hybridization and classification

Dudleya edulis , another member of the genus, occurs sympatrically within the range of D. stolonifera. D. edulis is the type species of subgenus Stylophyllum, whose name refers to the pencil-shaped leaves of D. edulis and its allies. Species in this subgenus, in addition to having thin, narrow leaves, also have spreading flowers, as opposed to the tubular, connate flowers as seen in other species (like Dudleya pulverulenta, for example). This difference between the spreading of the flowers was used by Moran as a diagnostic characteristic to separate the subgenera. [5]

Moran noted that Dudleya stolonifera was unusual because the flowers appear connate in bloom, but the carpels (female organs) are somewhat spreading, like in a Stylophyllum, instead of being connate like the flower in other similar Dudleya. Moran suggested that on this basis, D. stolonifera could be placed into Stylophyllum, as the attitude of the carpels was previously regarded as an important diagnostic characteristic. But with the broad rosette leaves and erect bright yellow petals resembling a typical Dudleya, Moran tentatively placed it in the subgenus Dudleya. [5]

The hybrid with Dudleya edulis, from the type description's article. Dudleya edulis x stolonifera from type description.jpg
The hybrid with Dudleya edulis, from the type description's article.
In addition to hybridizing with Dudleya edulis, this species also hybridizes with Dudleya lanceolata. Pictured is the flower of a hybrid. Dudleya stolonifera hybrid with lanceolata flower.jpg
In addition to hybridizing with Dudleya edulis, this species also hybridizes with Dudleya lanceolata . Pictured is the flower of a hybrid.

In addition to the Stylophyllum-like trait of the spreading carpels, D. stolonifera appears to readily hybridize with Dudleya edulis and produce fertile offspring. The hybrids branch dichotomously, have linear leaves, pale yellow petals, and flowers that are ascending at the tips but connate towards the base. Moran suggested that the interbreeding could imply a close relationship between the two species, but at the time, he noted there was little evidence available detailing crossability in Dudleya [5] (it would later be revealed that most species of Dudleya could readily hybridize with each other). [6] Less often it hybridizes with Dudleya lanceolata . [2]

The hybrid plant Moran described in his type description was collected growing with the plant of the type specimen of D. stolonifera, in Aliso Canyon. Also growing at the locality were secondary hybrid types, likely results of backcrossing. The secondary hybrids did not show random recombination of characters, but rather, were intermediate between the primary hybrids and the two parental species. [5]

Distribution and habitat

The plants flowering in habitat. Dudleya stolonifera 203602411.jpg
The plants flowering in habitat.

This species is only distributed in Orange County, California, where it is endemic to cliffs in the San Joaquin Hills. [3] It is only found in about six locations, [4] which include Aliso Canyon, Laguna Laurel Canyon, and Mathis Canyon. Occurrences in the easily-accessible areas of Aliso Canyon, where plants were once collected, were extirpated by development, with the destruction of that population occurring prior to listing of the species. [2]

Dudleya stolonifera grows on steep, middle Miocene sandstone cliffs, mostly in coastal sage scrub habitat, and sometimes in chaparral. [2] The cliffs are so steep they may be vertical or overhanging. The plant is only found on the north-facing cliffs. [4] It grows in very thin soils that support very few types of plants; the dudleya is usually found among only mosses and lichens, and sometimes the fern California polypody (Polypodium californicum). It may have an association with the lichen Niebla ceruchoides , which might act as a bed for the seeds of the dudleya when they fall to the ground. [2]

Conservation

This rare plant faces a number of threats to its survival. The effects of urban development may harm the plant. The habitat is too rugged in most areas to be directly developed, but associated changes to the habitat from nearby development may include the edge effect. When the plant was listed as threatened it was plucked from the wild by plant collectors; this is no longer thought to be a serious problem because the occurrences are too difficult for people to access. Grazing and trampling by livestock had a negative effect on the plant but grazing has been stopped in the area, causing the plant to rebound. Climate change is considered a threat today. Because the populations are few and small the plant may be extirpated by any major local event, such as wildfire, or by processes such as inbreeding depression. [2]

Competition with other plants, especially non-native species, threatens the Dudleya. In one area it is being displaced by invading Aeonium haworthii . [2]

See also

Related Research Articles

<i>Dudleya</i> North American succulent genus

Dudleya, commonly known as liveforevers is a genus of rosette-forming succulent plants in the stonecrop family, Crassulaceae, consisting of about 68 taxa in southwestern North America and Guadalupe Island. The species come in many forms, with some large and evergreen, others geophytic and deciduous. Yet, despite their dramatic variations in appearance, most species readily hybridize. The flowers of Dudleya have parts numbered in fives, with the petals arranged in tubular, star-shaped, and bell-shaped forms and, when fruiting, are filled with tiny, ovoid-crescent-shaped seeds.

<i>Dudleya abramsii <span style="font-style:normal;">subsp.</span> setchellii</i> Species of succulent

Dudleya abramsiisubsp. setchellii, known by common name as the Santa Clara Valley dudleya or Santa Clara Valley liveforever, is a member of the Dudleya genus of succulent perennials, members of the family Crassulaceae. The Santa Clara Valley dudleya, endemic to the Santa Clara Valley region in the southern San Francisco Bay Area, was listed on 3 February 1995, as an endangered species. It is considered to be a subspecies of Dudleya abramsii, but its taxonomic status is still unclear. Its closest relative is Dudleya cymosa subsp. paniculata, which is a morphologically similar sister taxon.

<i>Dudleya caespitosa</i> Species of coastal succulent plant from North America

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, this species is a highly variable complex of polymorphic and polyploid plants, closely related to numerous neighboring species such as Dudleya farinosa, Dudleya greenei and Dudleya palmeri. It is delimited from neighboring species on an arbitrary basis of distribution and chromosome number, and may not be immediately separable from the other species it approaches.

<i>Dudleya densiflora</i> Species of succulent

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 County, California, it is known only from three to five spots in the mountain range, with an estimated 1,700 individual plants remaining. Growing in the cracks of the granite slopes of three canyons in this single mountain range, it is threatened by human activity such as rock quarrying and off-trail recreation.

<i>Dudleya edulis</i> Species of succulent

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 edulis refers to the use of the young scapes as food by the Kumeyaay. It is native to Southern California and northern Baja California, and grows on rocky hillsides, cliffs, and bare rock.

<i>Dudleya farinosa</i> Species of succulent

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 typically found on oceanic bluffs just directly above the reach of the waves. Its appearance is characterized by lotus-like rosettes of beveled leaves, and in summer the plant erects a tall pink to red stem densely covered in foliage, topped with branches adorned with pale yellow flowers. The green or white rosettes of this plant can be seen covering stretches of rocky coast and nearby islets.

<i>Dudleya lanceolata</i> Species of succulent

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 through Ensenada in Baja California. It is characterized by green to purple lanceolate leaves, red, orange, or less commonly yellow petals, and is typically tetraploid. Despite its diversity, it is quite stable as a species, but hybrids may be discovered with other species of Dudleya, which can make it difficult to discern in areas where numerous species converge.

<i>Dudleya palmeri</i> Species of succulent

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 yellow or pink flowers. It is a polyploid species that closely resembles Dudleya lanceolata but has a coastal habit, and hybridizes with Dudleya caespitosa and Dudleya cymosa.

<i>Dudleya greenei</i> Species of succulent

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. It is a highly variable plant, presenting with multiple forms and varying levels of ploidy. Taxonomically, this species is an insular segregate of Dudleya caespitosa, and was placed as a stopgap taxon by Reid Moran in his 1951 thesis on the genus. It is characterized by white or green leaf rosettes, loomed over by inflorescences bearing pale yellow to white flowers. It is a member of the subgenus Dudleya, as it cannot be propagated from leaf cuttings, does not grow from a corm, and has tight petals.

<i>Dudleya verityi</i> Species of succulent

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 Camarillo and Thousand Oaks. It probably occurs in a few additional locations nearby which have not yet been officially vouchered.

<i>Dudleya attenuata</i> Species of succulent

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 that can often be found covered in a white epicuticular wax. The thin, sprawling stems branch to form the clusters of rosettes, with plants creating a "clump" up to 40 cm wide. The small flowers are white or yellow, with 5 spreading petals. It is a diverse, variable species that extends from the southernmost coast of San Diego County to an area slightly north of the Vizcaino Desert, hybridizing with many other species of Dudleya in its range. Some plants with white or pinkish flowers were referred to as Orcutt's liveforever, referring to a former subspecies split on the basis of the flower color.

<i>Dudleya ingens</i> Species of succulent

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, and in April to June is characterized by pale yellow to white pink-tinged flowers topping tall, reddish inflorescences. It has a stem clothed densely with old, leathery leaves, and the inflorescence may be nodding, with the floral branches bearing the flowers tending to unfurl like the fronds of a fern. It is similar in appear to Dudleya brittonii, but differs in range and chromosome number. This species is endemic to the state of Baja California in Mexico, being found from Santo Tomás to the southern coast of the state.

<i>Dudleya anomala</i> Species of plant

Dudleya anomala is a rare species of succulent plant in the family Crassulaceae commonly known as the Todos Santos liveforever. With a dense, cushion-forming habit, this leaf succulent is characterized by elongated stems, slightly sticky leaves, and bell-shaped flowers with white, spreading petals. This species is native to Baja California, Mexico, and is found primarily on islands and one coastal locality.

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.

<i>Dudleya cultrata</i> Species of succulent

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 with pale yellow petals that bloom from April to June. Although similar to Dudleya ingens, this species is most often seen growing sympatric with the larger, wax-covered Dudleya anthonyi. It is native to Baja California, occurring on the coast from Punta Colonet and San Quintin to El Rosario.

Dudleya cymosasubsp. costatifolia, known commonly as the Pierpoint Springs dudleya or the Pierpoint Springs liveforever, is a species of succulent plant in the family Crassulaceae, narrowly endemic to a locality in Tulare County, California, United States. It is a clumping plant with small rosettes and bright yellow flowers, resembling alpine cushion plants.

<i>Dudleya cymosa <span style="font-style:normal;">subsp.</span> pumila</i> Subspecies of plant

Dudleya cymosasubsp. pumila, most commonly known as the low canyon dudleya, chalky canyon dudleya or California live-forever, is a species of perennial succulent plant. It has diamond to spoon shaped leaves, sometimes coated with a fine white powder, and in May through July, bright red, orange or yellow flowers adorn the short inflorescence. A leaf succulent primarily found growing in rocky cliffs and slopes, it is endemic to California, and grows in the Transverse Ranges and South Coast Ranges, with some outlying populations. A variable plant, in some localities it is difficult to distinguish from other plants in the genus.

<i>Dudleya cymosa <span style="font-style:normal;">subsp.</span> cymosa</i> Subspecies of succulent perennial plant

Dudleya cymosasubsp. cymosa is a species of succulent perennial plant in the family Crassulaceae native to California. It is the autonymous subspecies for Dudleya cymosa, and is known by the common name canyon liveforever. It is native to the California Coast Ranges, the Sierra Nevada and the Santa Monica Mountains. It is characterized by bright-yellow, orange or red flowers and broad, wide leaves. This plant is commonly found growing on rocky outcrops, talus slopes, and in shaded canyons.

<i>Dudleya cymosa <span style="font-style:normal;">subsp.</span> marcescens</i> Subspecies of deciduous succulent plant

Dudleya cymosa subsp. marcescens is a species of summer-deciduous succulent plant known commonly as the marcescent dudleya or marcescent liveforever. Throughout the months of spring, it is characterized by a bloom of small, bright-yellow flowers with 5 petals, tinged with orange or red. It is a leaf succulent with a basal rosette, with the foliage withering in summer, going completely leafless, a neotenous trait in the genus. This species is endemic to the exposed volcanic rock of the Santa Monica Mountains in California, being found on shady slopes and outcroppings. It differs from its local congeners with its deciduous habit, slender caudex, and narrower leaf shape, although it is superseded in some of these characteristics by Dudleya parva, growing 13 km to the north, which has even narrower leaves and is quicker to lose them. Because of its restricted distribution and small size, it is vulnerable to habitat degradation and disturbance from acts of graffiti and rock climbers. It is listed as threatened by the United States Fish and Wildlife Service.

<i>Dudleya cymosa <span style="font-style:normal;">subsp.</span> agourensis</i> Subspecies of flowering plant

Dudleya cymosasubsp. agourensis, commonly known as the Agoura Hills dudleya or Agoura Hills liveforever, is a species of perennial succulent plant. A rare and critically imperiled species from the Santa Monica Mountains in California, it is characterized by glaucous, gray-purple leaves, bright yellow flowers, and ascending bracts. A leaf succulent, it is found growing on west to northwest-facing open, rocky volcanic slopes.

References

  1. 1 2 "Dudleya stolonifera". NatureServe Explorer. Arlington, Virginia: NatureServe. 2022. Retrieved 5 May 2022.
  2. 1 2 3 4 5 6 7 USFWS. Dudleya stolonifera Five-year Review. April 16, 2010.
  3. 1 2 3 4 McCabe, Stephen W. (2012). "Dudleya stolonifera". Jepson eFlora. Jepson Flora Project. Retrieved 5 May 2022.
  4. 1 2 3 4 5 6 Moran, Reid. "Dudleya stolonifera". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). New York and Oxford. Retrieved 5 May 2022 via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
  5. 1 2 3 4 5 6 Moran, Reid (1949). "Dudleya stolonifera, a new species from Orange County, California". Bulletin of the Southern California Academy of Sciences. 48: 105–114.
  6. Uhl, Charles H.; Moran, Reid V. (July 1953). "The Cytotaxonomy of Dudleya and Hasseanthus". American Journal of Botany. 40: 495–502.