Dudleya pulverulenta (Nutt.) Britt. & Rose

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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 larger 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 1000 kilometers, being found from Monterey County in California to the Sierra de San Borja in southern Baja California.

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.

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 corolla is the longest in the genus, adapted to hummingbird pollinators. The petals of the flower are red, while the sepals are covered in wax.

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.

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

The type specimen was collected by Thomas Nutall in San Diego, in May 1835.

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

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

Dudleya pulverulenta is native to California and Baja California.

Its range extends from extreme southern Monterey County southward to Punta Prieta in the central desert of Baja California. It is typically found in rocky cliffs, and canyons, generally under 1000 meters in elevation. 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.

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

Dudleya pulverulenta - Wikipedia

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