''Dudleya saxosa'' subsp. ''aloides'' is a species of

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

succulent In botany, succulent plants, also known as succulents, are plants with parts that are thickened, fleshy, and engorged, usually to retain water in arid climates or soil conditions. The word ''succulent'' comes from the Latin word ''sucus'', meani ...

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 The Peninsular Ranges (also called the Lower California province) are a group of mountain ranges that stretch from Southern California to the southern tip of the Baja California peninsula; they are part of the North American Coast Ranges, which ...

and desert mountains of

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. 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 ''Dudleya lanceolata'' is a succulent plant known by the common name lanceleaf liveforever or lance-leaved dudleya. It is an extremely variable and widely ranging species that occurs from Monterey County and Kern County in California south throug ...

''.

Description

A rosette-forming succulent that may be

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...

or summer deciduous. It typically has bright yellow or green flowers. This plant's basal rosette is formed on top of a

caudex A caudex (plural: caudices) of a plant is a stem, but the term is also used to mean a rootstock and particularly a basal stem structure from which new growth arises.pages 456 and 695 In the strict sense of the term, meaning a stem, "caudex" is m ...

(stem), which is 1 to 3 cm in diameter. There are 1 to 4 rosettes, and they may be 6 to 23 cm wide. The leaves are typically 4 to 15 cm long, and 6 to 25 mm wide, 2 to 5 mm thick, and their base is 10 to 25 mm wide. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

has a peduncle 10 to 51 cm tall, and 1 to 9 mm wide. The lower internodes are spaced over 5 mm. The peduncle then branches 3 times, with the floral shoots colored red or green. The terminal branches (cincinni) are wavy, 1 to 12 cm long, and have 2 to 20 flowers. The

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

s are around 4 to 6 mm long. The

petal Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...

s are 8 to 15 mm long, and are fused 1.5 to 3 mm. The petals are colored bright yellow or green, but rarely they are tinged with red. Flowering is from April to June

Taxonomy

Taxonomic history

This species was described as ''Dudleya aloides'' in 1903, based on a specimen collected from

San Diego County San Diego County (), officially the County of San Diego, is a county in the southwestern corner of the U.S. state of California. As of the 2020 census, the population was 3,298,634, making it California's second-most populous county and the fi ...

by Townshend Brandegee and examined by

Nathaniel Lord Britton Nathaniel Lord Britton (January 15, 1859 – June 25, 1934) was an American botanist and taxonomist who co-founded the New York Botanical Garden in the Bronx, New York (state), New York. Early life Britton was born in New Dorp, Staten Island, New ...

and Joseph Nelson Rose during their revision of North American Crassulaceae species. The two also described ''Dudleya grandiflora'', from Whitewater near Banning, California, also collected by Brandegee. A third taxon, the comparatively diminutive ''Dudleya delicata'', was also described by Britton and Rose, collected by LeRoy Abrams near

Julian Julian may refer to: People * Julian (emperor) (331–363), Roman emperor from 361 to 363 * Julian (Rome), referring to the Roman gens Julia, with imperial dynasty offshoots * Saint Julian (disambiguation), several Christian saints * Julian (give ...

. W.L. Jepson placed the species as '' Echeveria lanceolata'' var. ''composta''.

Reid Moran Reid Venable Moran (June 30, 1916 – January 21, 2010) was an American botanist and the curator of botany at the San Diego Natural History Museum from 1957 to 1982. Moran was the world authority on the Crassulaceae, a family of succulent plant ...

placed it as ''

'' ssp. ''aloides'' in 1951. Moran eventually combined ''Dudleya aloides'' as a subspecies of ''Dudleya saxosa'', forming the current combination in 1957. ''Dudleya grandiflora'' was recognized as synonymous with subspecies ''aloides'', although the plants called ''grandiflora'' are slightly larger than typical subsp. ''aloides''.

''Dudleya alainae''

In 1984, botanist Craig H. Reiser recognized a number of ''Dudleya'' occurring on the eastern side of the

Cuyamaca Mountains The Cuyamaca Mountains ( Kumeyaay: ''‘Ekwiiyemak''), locally the Cuyamacas, are a mountain range of the Peninsular Ranges System, in San Diego County, southern California. The mountain range runs roughly northwest to southeast. The Laguna Mount ...

as ''Dudleya alainae'', commonly known as the Banner dudleya. He recognized them as distinct based on diagnostic criteria that included sulphur-yellow flowers, (as opposed to bright yellow or greenish-yellow) a smaller inflorescence, and restricted montane habitat compared to subsp. ''aloides''. In 1986, another botanist, Kei M. Nakai, recognized ''Dudleya alainae'' as being synonymous with Rose's ''Dudleya delicata'' species, and therefore a synonym of ''Dudleya saxosa'' subspecies ''aloides''. The group of plants variously referred to as ''Dudleya alainae'' or ''delicata'' approach the lowland ''Dudleya lanceolata''. The chromosome number is ''n'' = 17. The treatment by botanist Stephen W. McCabe in the Jepson Manual regards ''Dudleya alainae'' as "in need of study."

Phylogeny

''Dudleya saxosa'' subsp. ''aloides'' has a chromosome number of ''n'' = ''17''. Despite its placement in the species '' Dudleya saxosa'', the other members, subsp. ''collomiae'' (''n'' = 68) and subsp. ''saxosa'' ( ''n'' = 68, ''n'' = 85), are disjunct (geographically isolated) in distribution and

polyploid Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei ( eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contain ...

. However, it also does not fit in with ''Dudleya lanceolata'' ( ''n'' = 34 ), as that species is tetraploid.

Distribution and habitat

This species is found primarily in the

and on desert mountains in the Mojave and Sonoran deserts in

, USA. It does not likely occur in Mexico. Plants in the northernmost section of the distribution tend to be smaller, while plants near the type locality of ''Dudleya grandiflora'', near Banning, are larger. Plants in western portion of the distribution in the Peninsular Ranges approach ''Dudleya lanceolata'', and hybrids are expected. This species is found growing in rocky, shaded slopes and crevices.

References

{{Taxonbar, from=Q24688570 saxosa subsp. aloides Endemic flora of California Natural history of the California chaparral and woodlands Natural history of the Peninsular Ranges Natural history of the Mojave Desert