''Pseudolithos'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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 ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s of the family

Apocynaceae Apocynaceae (, from '' Apocynum'', Greek for "dog-away") is a family of flowering plants that includes trees, shrubs, herbs, stem succulents, and vines, commonly known as the dogbane family, because some taxa were used as dog poison. Notable mem ...

, indigenous to arid areas of

Somalia Somalia, officially the Federal Republic of Somalia, is the easternmost country in continental Africa. The country is located in the Horn of Africa and is bordered by Ethiopia to the west, Djibouti to the northwest, Kenya to the southwest, th ...

Yemen Yemen, officially the Republic of Yemen, is a country in West Asia. Located in South Arabia, southern Arabia, it borders Saudi Arabia to Saudi Arabia–Yemen border, the north, Oman to Oman–Yemen border, the northeast, the south-eastern part ...

and

Oman Oman, officially the Sultanate of Oman, is a country located on the southeastern coast of the Arabian Peninsula in West Asia and the Middle East. It shares land borders with Saudi Arabia, the United Arab Emirates, and Yemen. Oman’s coastline ...

Description and naming

The plants were first described as a genus in 1965; the name ''"Pseudo-lithos"'' means ''"false-stone"'' and refers to their pebble-like appearance. It was originally proposed as ''Lithocaulon'' earlier in 1956, but this name was already in use for a genus of fossil

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

. All species in this genus are highly succulent, small in size, and exhibit

tessellation A tessellation or tiling is the covering of a surface, often a plane, using one or more geometric shapes, called ''tiles'', with no overlaps and no gaps. In mathematics, tessellation can be generalized to higher dimensions and a variety ...

on their stems' surface. Their small flowers appear on the spherical body's surface. ;Species

Taxonomy

Phylogenetic studies have shown the genus to be monophyletic, and most closely related to the widespread ''

Caralluma ''Caralluma'' is a genus of flowering plants in the family Apocynaceae, consisting of about 120 species. In 1795 William Roxburgh published the name '' Stapelia adscendens'' for a plant found in India. He commented that the name for the plant i ...

'' stapeliads of North Africa. Marginally more distantly related is a sister branch comprising the genera '' Echidnopsis'' and '' Rhytidocaulon''.P. Bruyns, C. Klak, P. Hanacek: ''Evolution of the stapeliads (Apocynaceae-Asclepiadoideae) - repeated major radiation across Africa in an Old World group. Molecular Phylogenetics and Evolution.'' 2014. v. 77, no. 1, p. 251--263. ISSN 1055-7903.

References

External links

Dave's Garden
photos Apocynaceae genera {{Apocynaceae-stub