Dudleya pulverulenta

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Chalk dudleya
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Status TNC G4.svg
Apparently Secure  (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. pulverulenta
Binomial name
Dudleya pulverulenta
Synonyms
  • Cotyledon peacockiiBaker
  • Cotyledon pulverulenta(Nutt.) Baker
  • Echeveria argenteaLem.
  • Echeveria peacockiiCroucher ex T.Moore & Mast.
  • Echeveria pulverulentaNutt.

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 one of the most specialized inflorescences in the genus, [2] adapted to hummingbird pollination through its red pendent flowers, the longest corolla, and the highest nectar output. Dudleya pulverulenta has the largest range of all 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. [3] It is closely related to Dudleya arizonica , a smaller desert species that tends to lack the specialized floral traits, and Dudleya anthonyi , which differs in a few morphological traits and is restricted to the San Quintín Volcanic Field.

Contents

Description

Detail of the flowers. Dudleyapulverulenta.jpg
Detail of the flowers.

Dudleya pulverulenta is a rosette-forming, succulent species of plant, covered in a distinctive chalky and mealy wax, known as a farina, or more technically, epicuticular wax. It is one of the largest species of Dudleya. All parts of the inflorescence are covered in a chalky wax, and the flowering stems may reach up to 150 cm (59 in) long.

Pollination syndrome

Dudleya pulverulenta exhibits a pollination syndrome uniquely adapted to hummingbirds. The flowers have long red petal tubes (corollas) and are unscented. The flowers hang downward (pendent), achieved by a twist at the base of the terminal inflorescence branches, known as the cincinni, which inverts the flowers from the typically erect or ascending position seen in other Dudleya. Like other hummingbird-adapted plants, the pendent flowers allow hummingbirds to readily reach the flowers from below, discouraging bees and other insect pollinators from easily landing. After flowering, the fruits are turned erect by a sharp turn of the branchlet connecting the flower to the inflorescence (the pedicel). [4]

This syndrome is only shared by the other two species in the genus, both close relatives of Dudleya pulverulenta: Dudleya anthonyi [3] and Dudleya arizonica . D. arizonica is similar in appearance, and approaches D. pulverulenta in many aspects, but most populations lack the downward-pointing flowers and unique fruiting behavior, instead having erect flowers and a more reduced size. [5] One of the only other hummingbird-specialized species in the genus, Dudleya rigida , found in far southern Baja California Sur, also has long, red, unscented pendent flowers, but the pendent flowers result from different orientations of the inflorescence structures compared to D. pulverulenta and its relatives. Other Dudleya, like Dudleya cymosa subsp. pumila and Dudleya lanceolata , have some adaptations to hummingbirds, but do not fully attain the traits of typical hummingbird flowers. [4]

Morphology

Dudleya pulverulenta grows a thick caudex, 4–10 cm (1.6–3.9 in) wide. As the plant grows older, the stem gradually becomes decumbent. The stem is densely clothed with old, dried leaves. Atop this stem is a solitary rosette, as the stems do not form axillary branches. The rosette reaches a width of 7–60 cm (2.8–23.6 in), and is composed of 40 to 60 wide, flat, fleshy, chalky white leaves which age to a pinkish papery texture. The leaves are shaped oblong, broadest at the base or upper third, with the tip acuminate to mucronate, or acute. The leaves are 8–25 cm (3.1–9.8 in) long by 3–10 cm (1.2–3.9 in) wide, and are 3–10 mm (0.12–0.39 in) thick. The epidermis of the plant is covered with a dense coating of chalky, powdery epicuticular wax. [3] [6] [7] [8]

The basal rosette. Joedecruyenaere - 26534268074.jpg
The basal rosette.

The peduncle is 30–100 cm (12–39 in) tall by 5–20 mm (0.20–0.79 in) wide, and is covered in 20 to 70 bracts. The bracts are spreading to deflexed, and are shaped cordate-ovate to suborbiculate, with an acuminate tip. The bracts measure 20–50 mm (0.79–1.97 in) long by 15–30 mm (0.59–1.18 in) wide, and may be a reddish color. The peduncle branches into 2 to 6 branches, which may or may not rebranch. There are 2 to 5 terminal branches, known as cincinni, that are nodding in youth but become spreading in age, and measure 10–50 cm (3.9–19.7 in) long. The cincinni are circinate, unfurling like the frond of a fern. The cincinni hold 10 to 30 flowers, and are twisted at the base, so that the flowers are on the underside. [3] [8]

Suspending the flowers pendent are the pedicels, which measure 10–35 mm (0.39–1.38 in) long. In age, the pedicels sharply bend in the near middle to bring the fruits to a more or less erect position. The calyx measures 5–9 mm (0.20–0.35 in) long by 5–8 mm (0.20–0.31 in) wide, with mostly acute sepals. The petals are 11–19 mm (0.43–0.75 in) long, and united for 6–10 mm (0.24–0.39 in) along their length. The apex of the petals is shaped acute to obtuse, with the tips erect. The sepals are waxy, while the petals are red, with some wax. [3] [7] [8]

Dudleya pulverulenta flowers in early summer, usually from May to July. [3] [8] Plants subject to full sun close their rosettes during the 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. [6]

Phytochemistry

Higher temperatures are tolerated well by Dudleya because of their epicuticular wax, which reflects light and prevents evaporation of water droplets. [9] [10]

Taxonomy

The type specimen was collected by Thomas Nutall in San Diego, in May 1835. [7] Dudleya puvlerulenta hybridizes with Dudleya lanceolata where they overlap in their ranges. [8]

Characteristics

Dudleya pulverulenta intergrades with both Dudleya anthonyi and Dudleya arizonica, and the boundaries between these three entities are not always clearly defined. Dudleya brittonii bears a superficial resemblance to this species, but differs significantly in its smaller yellowish-white flowers and dense inflorescence. [11] Two charts (below) compares the characteristics of these four species.

Comparison of vegetative features of Dudleya pulverulenta with similar species
SpeciesDudleya pulverulentaDudleya anthonyiDudleya arizonicaDudleya brittonii
Image Kaldari Dudleya pulverulenta 01.jpg Dudleya anthonyi 99791773.jpg Dudleya arizonica 6317711.jpg SLO Botanical Garden - Dudleya brittonii.jpg
Rosette width7–60 cm (2.8–23.6 in) [8] 15–50 cm (5.9–19.7 in) [11] 10–25 cm (3.9–9.8 in) [12] 10–50 cm (3.9–19.7 in) [11]
# of leaves40–60 [8] [11] 35–90, [11] 40–60 [13] 15–25 [11] [12] 40–120 [11]
Leaf shapeOblong, usually widest in distal 13 [3] [11] Oblong, widest at base [11] Oblong-oblanceolate to oblong-ovate [11] [12] Linear to oblong-lanceolate [11]
Leaf tipAcuminate, mucronate, to acute [8] [11] Acuminate or sharply acute [13] Long-acuminate [12] Long-acuminate [11]
Comparison of reproductive features of Dudleya pulverulenta with similar species
SpeciesDudleya pulverulentaDudleya anthonyiDudleya arizonicaDudleya brittonii
Image Dudleya pulverulenta cincinni 1.jpg Dudleya anthonyi 173754664.jpg Dudleya arizonica 2.jpg Dudleyabrittonii1.jpg
Peduncle length30–100 cm (12–39 in), [3] [8] 30–80 cm (12–31 in) [11] 40–70 cm (16–28 in), [11] 30–70 cm (12–28 in) [13] 15–60 cm (5.9–23.6 in) [12] 30–100 cm (12–39 in) [11]
# of fls. per cincinni10–30 [3] [11] 12–25 [11] 3–6, [11] [12] 4–20 [5] 5–20 [11]
Pedicel length5–30 mm (0.20–1.18 in), [8] [11] 10–35 mm (0.39–1.38 in) [3] 12–15 mm (0.47–0.59 in) [11] [13] 5–15 mm (0.20–0.59 in), [12] 5–20 mm (0.20–0.79 in) [5] 6–15 mm (0.24–0.59 in) [11]
Pedicels at anthesisPendent [3] [8] [11] Pendent [11] Erect, ascending, rarely spreading to pendent [12] [11] [5] Erect [11]
Petal colorRed, with some wax [8] [3] Deep red [11] [13] Red to apricot yellow [5] [12] Yellowish-white [11]
Sepal shapeTriangular to triangular-ovate, acute [11] Triangular-lanceolate to linear, pointed [11] Acute [11] Long-lanceolate, acute [11]

Distribution and habitat

Growing in habitat Flickr - brewbooks - Dudleya - Roadside succulent.jpg
Growing in habitat

Dudleya pulverulenta is native to California and Baja California. Its range extends from extreme southern Monterey County [14] southward to Punta Prieta in the central desert of Baja California. [15] It is typically found in rocky cliffs, and canyons, generally under 1000 meters in elevation. [8] 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. [6]

Plants are very rapid recolonizers as evidenced by proliferation on roadcuts or disturbed soil shortly after development. [6] 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. [16]

Cultivation

The plant tolerates full sun exposure or part shade. It is susceptible to aphid infestations which result in flower and rosette deformities. [6] It is a much hardier plant for the garden environment than the more commonly available Dudleya brittonii.

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. [6]

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, 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 blochmaniae</i> Species of succulent plant

Dudleya blochmaniae is a summer-deciduous succulent plant known by the common names Blochman's liveforever or Blochman's dudleya. This species of Dudleya survives part of the year with no aboveground presence, surviving as underground corm-like roots in deciduous months. It is characterized by white, star-shaped and spreading flowers that emerge after sufficient rainfall. It is found along the Pacific coast of the California Floristic Province, from the vicinity of San Luis Obispo in California to Punta Colonet in Baja California.

<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 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 brittonii</i> Species of succulent plant found in Mexico

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 plant have yellow leaves on a clustered rosette atop a large reddish-purple peduncle. The white form of the plant has a chalky epicuticular wax that reflects light and reacts with water. The green form of the plant is more common and found throughout a wider range. It is among the largest of the Dudleya.

<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 anthonyi</i> Species of succulent

Dudleya anthonyi is species of perennial succulent plant known commonly as the San Quintín liveforever. It is endemic to the San Quintín volcanic field, which encompasses the Bahia San Quintín and the adjacent Isla San Martín in Baja California. Dudleya anthonyi is a relatively large rosette-forming succulent and is characterized by its leaves and inflorescences that are coated in a white, chalky powder. It is quite similar to its close relative, the widespread Dudleya pulverulenta, but Dudleya anthonyi is distinguished by its narrower and acute basal leaves and bracts, along with narrower and pointed sepals and petals. Like its close relative, Dudleya anthonyi is one of the few members of the genus Dudleya that have a pollination syndrome almost exclusively favoring hummingbird pollinators, adaptations which are reflected by its long, red, and pendent flowers.

<i>Dudleya rigida</i> Species of flowering plant in the family Crassulaceae

Dudleya rigida is a species of succulent perennial plant in the family Crassulaceae known commonly as the La Laguna liveforever. Characterized by a tall inflorescence with pendant yellowish-red flowers, it is a very rare plant whose existence was doubtful until botanist Reid Moran accidentally re-discovered it. It is endemic to the Sierra de la Laguna in Baja California Sur, Mexico.

<i>Dudleya campanulata</i> Succulent plant native to Baja California, Mexico

Dudleya campanulata is a species of perennial succulent plant known by the common name as the Punta Banda liveforever, native to Baja California and endemic to the Punta Banda peninsula, a promontory south of Ensenada that encloses the southern limit of the Bahía de Todos Santos, a deepwater bay. One of many species of Dudleya native to the peninsula and surrounding islands, it is distinguished by its campanulate flowers and its occupation of a narrow habitat that consists of ocean bluffs on the southern end of the Punta Banda, near the well-known blowhole La Bufadora.

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

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.

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

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

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  3. 1 2 3 4 5 6 7 8 9 10 11 12 Moran, Reid. "Dudleya pulverulenta". Flora of North America. 8: 191.
  4. 1 2 Moran, Reid (1987). "Dudleya rigida Rose". Cactus and Succulent Journal of America. 1987 Sep-Oct: 187–194.
  5. 1 2 3 4 5 Moran, Reid. "Dudleya arizonica". Flora of North America. 8: 178, 190–191.
  6. 1 2 3 4 5 6 Thomson, Paul H. (1993). Dudleya and Hasseanthus Handbook. Bonsall Publications. ISBN   9780960206650.
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  9. Mulroy, Thomas W. (1979). "Spectral Properties of Heavily Glaucous and Non-Glaucous Leaves of a Succulent Rosette-Plant". Oecologia. 38 (3): 349–357. Bibcode:1979Oecol..38..349M. doi:10.1007/BF00345193. PMID   28309493. S2CID   23753011.
  10. Mulroy, T. W. (1976). The Adaptive Significance of Epicuticular Waxes in Dudleya (Crassulaceae). University of California, Irvine.
  11. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 Eggli, Urs; Hartmann, H.E.K., eds. (2003). "Dudleya". Illustrated Handbook of Succulent Plants: Crassulaceae. Springer. pp. 85–103. doi:10.1007/978-3-642-55874-0. ISBN   978-3-642-62629-6. S2CID   36280482.
  12. 1 2 3 4 5 6 7 8 9 McCabe, Stephen Ward (2012). "Dudleya arizonica". Jepson eFlora. Jepson Flora Project. Retrieved 21 December 2022.
  13. 1 2 3 4 5 Moran, Reid (1943). "Dudleya anthonyi". Desert Plant Life.
  14. McCabe, Stephen Ward (26 September 2019). "Succulent Poaching, Conservation,and the Mainland Dudleyas". Youtube. CNPS Santa Clara Valley Chapter. Archived from the original on 21 December 2021.
  15. 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.
  16. 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.