Dudleya gnoma

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Dudleya gnoma
Dudleya gnoma.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. gnoma
Binomial name
Dudleya gnoma
Synonyms

Dudleya greenei forma nanaMoranDudleya nana Moran ex P.H. Thomson

Contents

Dudleya gnoma is a rare species of succulent plant in the stonecrop family known by the common names munchkin liveforever and munchkin dudleya. [2] It is characterized by its diminutive stature, small yellow flowers, and distinctive white rosettes. It is endemic to the eastern portion of Santa Rosa Island, one of the Channel Islands of California, where it is known from one population at the type locality, containing three colonies of plants. [1]

Description

This is a compact plant growing from a caudex topped with clumps of rosettes containing up to 20 small leaves. The fleshy triangular leaves are white with a waxy, powdery coating of exudate. The leaves are dry, but not deciduous in summer. The plant produces an inflorescence and studded with small triangular bracts. It bears up to 10 flowers with yellow petals. [2]

Morphology

Plants may grow up to 10 cm (3.9 in) wide, with 1 to 24 individual rosettes on a plant. The rosettes are usually 0.8–5.1 cm (0.31–2.01 in) wide. The caudex (stem) is 1.2–2 cm (0.47–0.79 in) wide. The leaves are 0.5–1.3 cm (0.20–0.51 in) long by 0.6–2.5 cm (0.24–0.98 in) wide, shaped triangular to triangular-ovate. [2]

The peduncle is 2.5–13 cm (0.98–5.12 in) tall by 2–5 mm (0.079–0.197 in) wide. The inflorescence may branch up to 2 times. The terminal branches have 1 to 10 flowers on them. The flowers are suspended on pedicels 1–3 mm (0.039–0.118 in) long. The flowers have sepals 3.5–4 mm (0.14–0.16 in) long, 2–3 mm (0.079–0.118 in) wide. The petals are 8–9 mm (0.31–0.35 in) long, 3 mm (0.12 in) wide, and are fused in the lower 1–2 mm (0.039–0.079 in). The keels of the petals may be more or less glaucous. [2]

Plants flower from May through June. Chromosome number is 2n = 68. [2]

Taxonomy

Taxonomic history

The population was discovered in the 1950s and assumed to be a form of Dudleya greenei , a plant also occurring on the island which is similar but larger and contains the same number of chromosomes. [3] [4] Reid Moran regarded it as Dudleya greenei forma nana in an unpublished description. In the publication of the Dudleya and Hasseanthus Handbook, Paul H. Thomson separated the plant as a distinct species, Dudleya nana (1988), based on Moran's description and the cultivated "White Sprite" variety. However, Thomson's description was not valid. He failed to accurately place the collection number, collector, collection date, type specimen, or the location of a type specimen in a herbarium, which meant that Thompson's description did not constitute a valid publication according to the International Code of Botanical Nomenclature. [5]

Growing in the shallow Miocene volcanic substrate on Santa Rosa. Joedecruyenaere - 35745252185.jpg
Growing in the shallow Miocene volcanic substrate on Santa Rosa.

In 1997, botanist Stephen W. McCabe gave the species a proper description as Dudleya gnoma. The species was placed in the subgenera Dudleya. Although it is included in subgenus Dudleya, some of the petals approach a degree of spreading seen mostly in subgenus Stylophyllum plants like Dudleya traskiae . The habit of the plants to grow on flat areas and in shallow soil is also similar to the subgenus Hasseanthus. The overwhelming majority of the other characteristics, including the average petal altitude, broad leaf bases, and evergreen nature, does place it in subgenus Dudleya. [5]

Characteristics

This plant differs from Dudleya greenei, which it was originally assigned to, in a number of different ways. The rosettes of D. gnoma are much smaller, and the leaves are shaped triangular to triangular-ovate, as opposed to the larger, non-triangular and variously shaped leaves of D. greenei. The bracts, flowers, and pedicels of D. gnoma are all smaller and shorter than in D. greenei. [5]

In D. gnoma, the base of the pedicel of the first flower is 2 to 4 mm from the base of the lowest cincinnus. In D. greenei, the base of the pedicel of the first flower is usually 0 mm from the base of the first cincinnus, as it is directly attached to it. In D. gnoma, there are usually two branches to the inflorescence, and the two infrequently rebranch after. In D. greenei, there are usually three branches in the inflorescence, and they may rebranch and ascend. [5]

In horticultural or lush, rainy conditions, D. gnoma may produce additional branches on the inflorescence. The habitat of both species is also different. D. gnoma is found on shallow soils in flat areas, while D. greenei is found on cliff faces in canyons or seacliffs. Even the smallest flowering forms of Dudleya greenei are distinguished from D. gnoma, because they have blunter leaf apices and leaves that are oblong and more round in cross section. [5]

Distribution and habitat

Population in habitat. Joedecruyenaere - 35576378782.jpg
Population in habitat.

This species is distributed on Santa Rosa Island, one of the Channel Islands of California in the United States. It is found on a ridge on the eastern side of the island. This species grows on rocky slopes with shallow volcanic soils. [2] [5]

The population is protected from nearby grazing cattle by a fence. [1] It still faces threats from deer, which can get past the fence, a limited gene pool, and the fact that a single severe event such as a drought, could eliminate the single population. It also faces the potential threat of plant poachers. [1]

Horticulture

Though rare in the wild, this dudleya is kept in cultivation by gardeners and enthusiasts of succulents, and a cultivar called 'White Sprite' is popular. [3] [6] The cultivar was first introduced and named by Abbey Garden in the early 1970s from a plant of Dorothy Dunn, who in turn acquired her material from Reid Moran. The International Succulent Institute also distributed one of Moran's specimens, Moran 3364, as 'White Sprite' in 1977. [5]

Although the plant is available in cultivation, the species is more difficult to maintain than other Dudleya species. Supplemental watering in summer may damage or even kill the roots, and leads to often little or stunted growth. [5]

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, 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 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 candelabrum</i> Species of succulent plant from the U.S.

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, where it is found in open rocky places and north-facing slopes. It is characterized by thin, spade-shaped green leaves and an inflorescence covered in long, reflexed bracts, with pale yellow flowers. It has been threatened by poachers shipping plants to South Korea.

<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 ocean bluffs just directly above the reach of the waves, and sometimes inland. Its appearance is characterized by lotus-like rosettes of beveled leaves, and in summer the plant erects a tall pink to red peduncle densely covered in bracts, topped with branches of 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 pulverulenta</i> Species of succulent plant found in the U.S. and Mexico

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 its habitat. It is also regarded as one of the most distinctive members of the Dudleya, with the most advanced inflorescence in the genus, consisting of pendant, hummingbird pollinated flowers, the longest corolla, and the highest nectar output, along with the largest range of all the Dudleya, over 1,000 kilometres (620 mi), being found from southern Monterey County in California to the Sierra de San Borja in southern Baja California.

<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 plant from the U.S.

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 appearance 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 guadalupensis</i> Species of succulent plant from Mexico

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, green, and a waxy white. It is characterized by dense leaves that fold over the center in dormancy, a curving, sinuous flower stalk, and white, cup-shaped flowers. It is endemic to the rocks and islets off of Guadalupe Island, an isolated volcanic island in the Pacific Ocean located 241 kilometers off of the coast of Baja California.

<i>Dudleya pauciflora</i> Species of succulent plant from Mexico

Dudleya pauciflora is a species of succulent plant in the stonecrop family known by the common name few-flower liveforever. It is characterized by its small crowded rosettes of narrow leaves and its colorful inflorescence with red-yellow flowers. Found growing on rocky outcrops and cliffs in the high elevation mountains of the Sierra de San Pedro Martir and the Sierra de San Borja, it is endemic to the state of Baja California, Mexico.

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.

<i>Dudleya arizonica</i> Species of perennial

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 rosette of succulent leaves. It resembles a reduced desert form of the more coastal chalk dudleya, Dudleya pulverulenta, but differs in its smaller stature, lower number of leaves, and orientation of the flowers. Native to the southwestern United States and northwestern Mexico, it is widespread in range, but is primarily found in scattered, widely separated localities. It can be found as far west as coastal Ensenada to the desolate desert ranges of Nevada. It is one of two species of Dudleya that occur in Arizona, the other being Dudleya saxosa subsp. collomiae, and is the only species on mainland Mexico and in Utah.

<i>Dudleya nubigena</i> Species of succulent plant from Mexico

Dudleya nubigena is a species of succulent plants in the family Crassulaceae. It is a rosette forming perennial with flattish leaves. Endemic to southern Baja California Sur, the species is found in the Sierra de la Laguna and the surrounding lowlands, a small southern portion of the Sierra de la Giganta, and on Isla Espíritu Santo, with a subspecies endemic to Cerralvo Island.

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.

References

  1. 1 2 3 4 "Dudleya gnoma". NatureServe Explorer. Arlington, Virginia: NatureServe. 2022. Retrieved 3 April 2022.
  2. 1 2 3 4 5 6 McCabe, Stephen W. (2012). "Dudleya gnoma". Jepson eFlora. Jepson Flora Project. Retrieved 3 April 2022.
  3. 1 2 Flora of North America
  4. Stephens, T. Arboretum helps protect rare island succulents. UC Santa Cruz Currents October 30, 2000.
  5. 1 2 3 4 5 6 7 8 McCabe, S. (1997). Dudleya gnoma (Crassulaceae): A new species from Santa Rosa Island. Madroño 44 48-58.
  6. "Dudleya 'White Sprite'". Archived from the original on 2011-06-14. Retrieved 2010-12-14.