Origin and Habitat: USA (California: North Desert Mts., West Panamint Mts.) and probably in northern Baja California. Not frequent.
Altitude range: 1100-2200 metres above sea level
Habitat and ecology: North-exposed granite or limestone slopes. rocky hillsides and canyon walls, Lower Sonoran Zone, western margins of the Colorado Desert.
Synonyms:
See all synonyms of Dudleya saxosa
Description: Dudleya saxosaSN|32637]]SN|32637]] (ssp. saxosa) The three geographically isolated subspecies of Dudleya saxosaSN|32637]]SN|32637]] differ mostly in size of parts and in level of ploidy.
Stems: Short, simple or apically branched, cespitose, 1 - 1.5 cm in diameter, axillary branches absent.
Rosettes: 3-10(-12) cm in diameter, with 10 - 25 leaves, solitary or few in a clump (rarely up to 10 together).
Leaves: Erect or ascending, succulent, oblong to oblong-lanceolate, flat on upper surface, rounded beneath, acute, weakly attenuate, 3-9(-15) cm long, 05-15(-20) mm broad, 2-5 mm thick , base 1-2.5 cm wide young glaucous, later more or less green often with reddish tips.
Inflorescence (cyme): Scape (5-)10-20(-35) cm tall, 4-9 mm thick, red, with triangular-lanceolate leaves. Inflorescence obpyramidal, often reddish, mostly 4-10(-20) cm in diameter, with (1-)2-3(-5) branched (usually 1- branched) scorpioid. Branches , simple or 1 times bifurcate, not curved (flowers on topside), but somewhat sinuate when old, 1-4(-12) cm long, cincinni 2–3, 2–20-flowered, circinate, 1–18 cm long. Pedicels 5 - 20 mm long.
Flower: Calix 4 - 6.5 mm in diameter, lobes (sepals) triangular, acute, (2.5-)3-5(-6) mm long, 2.5-4 mm wide. Petals oblong-lanceolate or oblong-oblanceolate, (8-)9-12(-15) mm long, 2.5-4 mm broad, connate for1-5-3 mm, bright yellow or greenish, often marked with red and thus appearing orange, tube 1-2.5 mm, lobes apically recurved, acute. Nectaries whitish. Ovaries connivent,erect, 5.5 -9.5 mm, green: Styles 1-1.5 mm long.
Blooming season: Flowers April to June
Chromosome number: n = 68, 85.
Subspecies, varieties, forms and cultivars of plants belonging to the Dudleya saxosa group
Bibliography: Major references and further lectures
1) Reid V. Moran Dudleya saxosa (M. E. Jones) Britton & Rose [family CRASSULACEAE] in: “Flora of North America”, Vol 8, retrieved 01 March 2016 from <http://plants.jstor.org/stable/10.5555/al.ap.flora.fna008000376>
2) Urs Eggli “Illustrated Handbook of Succulent Plants: Crassulaceae” Springer Science & Business Media, 01 January 2003
3) Forrest Shreve, Ira Loren Wiggins “Vegetation and Flora of the Sonoran Desert”, Volume 1 Stanford University Press, 1964
Cultivation and Propagation: This slow growing specie is often grown and makes an attractive plant. It is much admired but less easily grown than some others. Grow it as a house or conservatory plant in a porous mix, or as a garden perennial where winters are mild and summers dry. Dudleyas are hardy in USDA Zoned 9-12, the plant is highly heat and drought tolerant during the summer months and prefers moist cool winters. Powdery white leaves make these plants standouts, but avoid touching them as they are easily and permanently marked by finger marks. All of the plants in the Dudleya genus are known to live up to 100 years.
Soil: They do best in very well-drained, sandy or gravely soil. As an ornamental it is also grown in containers where it stays smaller than its outdoor brethren. In pots they need a very porous mix soil (e.g. 2 parts peat moss to 1 part loam to 1 part of pumice).
Exposure: It requires ample sun, but provide midday shade where summers are hot. The quality of light is much more important than the quantity, the plants contain farinose powder which makes them really effective for ultraviolet reflectivity. Low light situations might be stressful and create a susceptibility to mealy bug infestation.
Watering: Dudleyas are summer-dormant winter growers that require fresh air, exceptionally well- drained soil, and don't water them in summer even if they appear crisp and miserable; they're dormant and unused to summer rainfall. However, they do appreciate an occasional misting suggestive of coastal fog (provide water in spring and autumn). In the summer the roots are unable to absorb the water so any excess of water simply rots them because of their dormant state.
Maintenance: Remove spent flower stems for appearance. The older leaves of Dudleyas wither but remain attached to the stem. Whether or not they should be removed is disputed, but they provide a hiding place for pests and some growers preference to remove them.
Uses: This can become a beautiful pot plant with pretty inflorescences with the right care.
Propagation: Dudleyas has been found to be propagated through both seed and vegetative, although vegetative propagation by offsets in spring or early summer is not only more popular but it is much easier to do. Dudleya should be planted at an angle. This prevent s the buildup of water in the leaves, which may lead to the leaves rotting. The vegetative propagation process needs to be done with temperatures reaching 21 degrees C. Let dry the cutting for about five to ten days and put the the cutting into the rooting compost (2 parts perlite and 1 part cactus potting mix). After finishing this you then place the pot in a warm, sheltered, but very bright filtered light area with no direct sunlight, you do not want the leaves to dehydrate. During the rooting period make sore to limit water, the rooting will take around 2 weeks, after roots transplant into the growing container. One thing to remember when rooting cuttings, overhead watering is not good for it, apply only to the soil line. The seeds do not need to be covered but do need a moistened soil for germination. Placing them into a mist house at an optimal 20-21 degrees Celsius with sufficient lighting resulting in germination. Germination occurs in just two weeks.
Dudleya saxosa subs. collomiae (Rose) R.Moran
