Dudleya greenei

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Dudleya greenei
Greene's dudleya imported from iNaturalist photo 20020748 on 21 December 2021.jpg
Status TNC G3.svg
Vulnerable  (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. greenei
Binomial name
Dudleya greenei
Dudleya greenei range map.png
Natural range of Dudleya greenei
Synonyms [2]
  • Cotyledon greenei(Rose) Clokey
  • Dudleya echeverioidesJohanss.
  • Dudleya hoffmanniiJohanss.
  • Dudleya regalisJohanss.
  • Echeveria greenei(Rose) A.Berger

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, [3] presenting with multiple forms and varying levels of ploidy. Taxonomically, this species is an insular segregate of Dudleya caespitosa , [4] 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. [5] 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. [6]

Contents

Description

Morphology

In habitat. Greene's dudleya imported from iNaturalist photo 35476236 on 20 December 2021.jpg
In habitat.

This species of Dudleya may or may not be caespitose; it can form clumps up to 1 meter wide. It may have anywhere from 1 to 100+ rosettes. Each rosette can range anywhere from 5 to 46 cm wide. The caudex is 2 to 5 cm wide, and may become elongated. Unlike the nearby D. candelabrum , the caudex is not swollen at the base. The leaves are evergreen, and are 3 to 22 cm long, 1 to 3.5 cm wide, and 4 to 8 mm thick. The leaf shape is variable. They may be covered in a white epicuticular wax, or present green. The base of the leaf is generally 1 to 3 cm wide, and may wound red or yellow when detached from the stem. The tip of the leaf is generally acute, while the margins of the leaves generally have 0 to 1 angles between the upper and lower leaf surfaces. [5]

The nascent inflorescence. Greene's dudleya imported from iNaturalist photo 134764950 on 20 December 2021.jpg
The nascent inflorescence.

The peduncle is 4.5 to 50 cm tall, and 3 to 5 mm wide. There are typically 3 first degree branches on the inflorescence, which may rebranch 0 to 2 more times. The terminal branches are 1 to 9 cm long, and hold 2 to 15 flowers. The bracts are 10 to 30 mm long, and 5 to 12 mm wide. The bracts are shaped lanceolate to oblong, and are more or less thick; they are also not bent backwards (reflexed). [3] The pedicels are 1 to 5 mm long.

The flower has sepals 1.5 to 5 mm long, shaped deltate. The petals are 8 to 12 mm long, 3 to 5 mm wide, and are connate (fused to form a tubular corolla) 1.5 to 2.5 mm. The petals are shaped elliptic, have an acute apex, and are pale yellow to more or less white (especially white on the margins). The pistils are connivent and erect. [5] [4]

Flowering is from May to July. [5] [4]

Taxonomy

As defined by botanist Reid Moran, this species is an insular segregate of the Dudleya caespitosa complex. It is an extremely variable species that appears somewhat different on each island. There are little characteristics that can unambiguously separate D. greenei and D.caespitosa, although there are extreme, unmatched characteristics on both sides, such as out-curved petals and numerous rosettes leaves in D. greenei and red petals and thin leaves in D. caespitosa. The chromosome number is n = 34, 51, making it tetraploid and hexaploid in respect to the basic chromosome number of the genus. [7]

Taxonomic history

The first collection of this plant was made by Edward Lee Greene in 1886, on Santa Cruz Island in the Channel Islands of California. In their 1903 work on the North American Crassulaceae, Joseph Nelson Rose and Nathaniel Lord Britton circumscribed the genus Dudleya . The species Dudleya greenei was described off of Greene's collection by Rose. [8]

in 1932, botanist Donald A. Johansen, writing in his "Contributions Toward a Monograph of the Genus Dudleya," published within the Cactus and Succulent Society of America's journal, described two new species from the Channel Islands based on collections made by Ralph Hoffmann, a naturalist and explorer of the islands who passed away the same year after an accident on San Miguel Island. Hoffmann made several collections of Dudleya from San Miguel Island, its adjacent islets, and Santa Rosa Island. [9] [10]

Johansen named Dudleya hoffmannii and Dudleya regalis from collections by Hoffmann on Prince Island, which is off of San Miguel Island. D. regalis was noted as distinct for its white flowers and size and number of rosettes. The specific epithet of D. regalis is a reference to the name of the island, and also due to their "regal" appearance described by Johansen. [9] D. hoffmannii, named in honor of Hoffmann a few months after his fatal fall, was noted for its similarities to Dudleya septentrionalis (now Dudleya farinosa ) and Dudleya helleri (now Dudleya caespitosa). [10]

In 1935, Johansen named Dudleya echeverioides based on specimens collected in 1930 by the late Hoffmann on Santa Rosa Island. Johansen recognized D. echeverioides as being unusually distinct based on the sweetly-scented flowers, that he described as having an odor "unmistakably resembling that of woodland violets." The specific epithet was named after the plant's appearance to other succulents in the genus Echeveria . [11]

Reid Moran, working on the taxonomy of the genus for his 1951 dissertation, revisited several of the new plants named by Johansen. Moran found D. hoffmannii to be similar to D. farinosa, corroborating Johansen's report. Gentry also reported the plants as D. farinosa. Moran recognized that D. regalis differed from D. hoffmannii with its narrower green leaves, more complex inflorescences, and more spreading petals. However, when in the field, Moran found both of these plants as well as ones with various combinations of their character. As all plants studied cytologically were revealed to be hexaploid, and with the plants intermingling both morphologically and being interfertile, the segregation of both entities was dropped in favor of placing them under D. greenei. [7]

Plants matching the description of the odorous flowers of D. echeverioides could not be located by Moran, and with an apparent loss of the type specimen and a lack of an illustration, the original description made no distinction as to why the plant would be morphologically different from D. greenei. Moran then subsequently combined it with D. greenei. [7]

Although Moran kept D. greenei alive as a taxon as "a matter of temporary convenience," he never published his 1951 dissertation, [7] and thus this species has remained valid into the 21st century. [5]

Distribution and habitat

This species is distributed throughout the northern Channel Islands: Santa Cruz, San Miguel, and Santa Rosa islands with the exception of Anacapa. Plants on Anacapa are D. caespitosa. It is found on coastal cliffs and rock outcrops. [5] Tetraploid representatives of this species are also present on Catalina Island. [6] However, some plants with campanulate flowers on Catalina may be of hybrid origin between Dudleya greenei and Dudleya virens subsp. insularis. [6] [12]

Conservation

This species is threatened by trampling from cattle and other feral herbivores on Santa Rosa Island. It is also threatened by poaching. [1]

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 candelabrum</i> Species of succulent

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 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 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 stolonifera</i> Species of succulent

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

<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 gnoma</i> Species of succulent plant

Dudleya gnoma is a rare species of succulent plant in the stonecrop family known by the common names munchkin liveforever and munchkin dudleya. 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.

<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>

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 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.

<i>Dudleya gatesii</i> Species of succulent plant

Dudleya gatesii, known by the common name as Gates'liveforever, is a species of perennial succulent plant in the family Crassulaceae. It is native to the central desert of the Baja California peninsula, found growing along dry and rocky outcroppings. It is characterized by red inflorescences topped with white flowers, bracts that are often reflexed downwards, and a rosette of dark-green leaves turning reddish.

<i>Dudleya pachyphytum</i> Species of succulent plant

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 and adorned by white flowers in bloom, it is regarded as one of the most attractive and charismatic members of its genus. It is endemic to the foggy northern end of Mexico's Cedros Island, occupying an ecological niche shared with the Cedros Island Pine.

<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 saxosa <span style="font-style:normal;">subsp.</span> collomiae</i>

Dudleya saxosa subsp. collomiae, known by the common name Gila County liveforever, is a subspecies of perennial succulent plant within the genus Dudleya native to central Arizona. It is characterized by showy bright-yellow flowers on an upright inflorescence colored pink, red or orange. The leaves are green or covered in a white, powdery wax. This species is found growing in rocky slopes, canyons, and crevices, and often on Sonoran Desert sky islands.

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

Dudleya saxosasubsp. aloides is a species of perennial succulent plant in the family Crassulaceae known by the common names desert dudleya or desert savior. It is a rosette-forming species widely distributed throughout the Peninsular Ranges and desert mountains of California in the United States. It is characterized by bright-yellow or greenish-yellow flowers, and can be found in shaded crevices and slopes. Plants in western half of the range may grade into Dudleya lanceolata.

<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.

Dudleya virens subsp. extima is a subspecies of succulent plant in the family Crassulaceae commonly known as the Guadalupe green liveforever. It is a rosette-forming leaf succulent, with both green and white waxy foliage. It has white flowers with spreading petals that bloom from May to June. It is a somewhat small plant, continuing a southward trend of decreasing size relative to other Dudleya virens subspecies. This plant is endemic to Guadalupe Island in the eastern Pacific Ocean, which is 241 kilometers off of the Baja California coast. It is very rare, with this plant only surviving on sheer cliff faces and canyons, out of the reach of the former feral goat population rampant on the island. It closely resembles a miniature version of Dudleya virens subsp. virens, but it may be more nearly related to the local Dudleya guadalupensis.

References

  1. 1 2 "Dudleya greenei". NatureServe Explorer. NatureServe. 2021. Retrieved 21 December 2021.
  2. "Dudleya greenei". Plants of the World Online . Royal Botanic Gardens, Kew . Retrieved 8 April 2022.
  3. 1 2 McCabe, S. (1997). Dudleya gnoma (Crassulaceae): A new species from Santa Rosa Island. Madroño 44 48-58.
  4. 1 2 3 Moran, Reid. "Dudleya greenei". Flora of North America. Flora of North America Association. 8: 179, 189.
  5. 1 2 3 4 5 6 McCabe, Stephen Ward (2012). "Dudleya greenei". Jepson eFlora. Jepson Flora Project (eds.). Archived from the original on 2021-09-08. Retrieved 20 December 2021.
  6. 1 2 3 Uhl, Charles H.; Moran, Reid V. (July 1953). "The Cytotaxonomy of Dudleya and Hasseanthus". American Journal of Botany. 40 (7): 495–502. doi:10.1002/j.1537-2197.1953.tb06510.x.
  7. 1 2 3 4 Moran, Reid V. (1951). "A Revision of Dudleya (Crassulaceae)". Dissertation (Unpublished). University of California.
  8. Rose, Joseph Nelson; Britton, Nathaniel Lord (1903). "New or Noteworthy North American Crassulaceae". Bulletin of the New York Botanic Garden. 3: 17.
  9. 1 2 Johansen, Donald A. (November 1932). "Contributions Toward a Monograph of the Genus Dudleya -- III". Cactus and Succulent Journal. Cactus and Succulent Society of America. 4 (5): 287 via archive.org.
  10. 1 2 Johansen, Donald A. (September 1932). "Contributions Toward a Monograph of the Genus Dudleya -- II". Cactus and Succulent Journal. Cactus and Succulent Society of America. 4 (3): 243 via archive.org.
  11. Johansen, Donald A. (February 1935). "Contributions Toward a Monograph of the Genus Dudleya -- VI". Cactus and Succulent Journal. Cactus and Succulent Society of America. 6 (8): 122 via archive.org.
  12. Moran, Reid (1995). "The Subspecies of Dudleya virens (Crassulaceae)". Haseltonia. 3: 1–9. Thomson (1993: 198) described D. sproulii from plants he said were brought from Catalina long before by Fred Sproul. A plant of it Thomson sent Dr. Uhl proved to be triploid. The chromosome number and the ascending petals (his Plate 47: 4) together suggest that this may be a hybrid of the diploid D. virens insularis with tetraploid D. greenei, as indeed Thomson thought possible.