Dudleya pulverulenta

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Dudleya pulverulenta
Dudleya pulverulenta 1.jpg
Scientific classification edit
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Saxifragales
Family: Crassulaceae
Genus: Dudleya
Species:
D. pulverulenta
Binomial name
Dudleya pulverulenta

Dudleya pulverulenta is a species of perennial succulent plant known by the common names chalk lettuce, chalk dudleya, and chalk liveforever. Native to California and Baja California, it is one of the larger Dudleya, with a silvery, waxy rosette that may greatly contrast with its habitat.

Description[]

The plant grows one of the thickest stems in the genus. As the plant grows older, the stem gradually begins to tilt and grow until the plant is prostrate on the ground. Atop this stem is a rosette of 40 to 60 wide, flat fleshy leaves of pale green which age to a pinkish papery texture. The rosettes are usually solitary, but sometimes they may present anywhere from 3 to even 23 rosettes in a hen-and-chicks fashion. The leaves are oblong, broadest at the base or upper third, with the tip acuminate to mucronate. The epidermis of the plant is covered with a dense coating of chalky, powdery epicuticular wax.[1][2][3]

Detail of the inflorescence on a cultivated plant

The peduncle is among the largest of the genus, and the entire stalk may reach up to 1.2 meters (4 feet). Its pale green or white inflorescences are nodding in youth, but spread in age. The inflorescences bear many flowers, each on a long pedicel.The petals of the flower are red, while the sepals are covered in wax.[1][3]

Dudleya pulverulenta is not noted for its longevity and may only live up to 2 or 3 years in cultivation, but some specimens in the wild may be over 40 years old in a most optimal location. When the plant dies, the rosette takes on a withered, ashy gray appearance, resembling a bird's nest. It is important to note whether the center leaves of the rosette are still alive, as the dormant plant will often surround a few live leaves with a ring of withered leaves until the next growing season pushes them down.[1]

The plant flowers from May to July. Plants subject to full sun go close their rosettes in summer, and in July to August the leaves will begin to fold upward and inward, "shrinking" in the heightened temperatures. Plants on north-facing or shaded slopes are less likely to close their rosettes.[1][3]

Higher temperatures are tolerated well by Dudleya because of their epicuticular wax, which reflects light and prevents evaporation of water droplets.[4][5]

Distribution and habitat[]

Growing in habitat

Dudleya pulverulenta is native to California and Baja California. Its range extends from San Luis Obispo southward to Punta Prieta in the central desert of Baja California.[6] It is typically found in rocky cliffs, and canyons, generally under 1000 meters in elevation.[3] It is primarily a plant of coastal distribution and can often be found within 12 miles of the coast, and more inland occurrences are typically in valleys where the heat is moderated by elevation or coastal influence.[1]

Plants are very rapid recolonizers as evidenced by proliferation on roadcuts or disturbed soil shortly after development.[1] Their habitat preference for rocky, shallow soils and open habitats mean that fuel is limited in proximity to the plants, enabling them to survive wildfire. The plant will resprout after fire.[7]

Taxonomy[]

The type specimen was collected by Thomas Nutall in San Diego, in May of 1835.[2]

Dudleya pulverulenta grades into the similar species of Dudleya anthonyi and Dudleya arizonica, both of which have been sometimes regarded as subspecies.[2] Dudleya brittonii shares an overlapping distribution in Baja California and resembles a much larger version of D. pulverulenta. Both are distantly related.[1]

Dudleya puvlerulenta hybridizes with Dudleya lanceolata where they overlap in their ranges.[3]

Cultivation[]

The plant tolerates full sun exposure or part shade. It is susceptible to aphid infestations which result in flower and rosette deformities.[1] It is a much hardier plant for the garden environment than the more commonly available Dudleya brittonii.

References[]

  1. ^ Jump up to: a b c d e f g h Thomson, Paul H. (1993). Dudleya and Hasseanthus Handbook. Bonsall Publications. ISBN 9780960206650.
  2. ^ Jump up to: a b c Moran, Reid V. (1943). "DUDLEYA PULVERULENTA (Nutt.) Br. & R.". Desert Plant Life.
  3. ^ Jump up to: a b c d e McCabe, Stephen Ward (2012). "Dudleya pulverulenta". Jepson eFlora. Jepson Flora Project. Retrieved 15 September 2021.
  4. ^ Mulroy, Thomas W. (1979). "Spectral Properties of Heavily Glaucous and Non-Glaucous Leaves of a Succulent Rosette-Plant". Oecologia.
  5. ^ Mulroy, T. W. (1976). The Adaptive Significance of Epicuticular Waxes in Dudleya (Crassulaceae). University of California, Irvine.
  6. ^ Rebman, J. P.; Gibson, J.; Rich, K. (2016). "Annotated checklist of the vascular plants of Baja California, Mexico" (PDF). San Diego Society of Natural History. 45: 133.
  7. ^ Kellog, E (May 2005). "Post-fire Monitoring and Management Strategy for Blossom Valley Habitat Conservation Area" (PDF). Center for Natural Lands Management. Tierra Data, Inc: 23 – via San Diego Management & Monitoring Program.

External links[]

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