''Euphorbia flanaganii'', commonly known as Transkei medusa's head, is a succulent plant that belongs to the family

Euphorbiaceae Euphorbiaceae, the spurge family, is a large family of flowering plants. In English, they are also commonly called euphorbias, which is also the name of a genus in the family. Most spurges, such as '' Euphorbia paralias'', are herbs, but some, ...

. Due to the breadth of the Euphorbiaceae, little research specific to ''E. flanaganii'' has been conducted.

Taxonomy

It is believed to be closely related to ''E. hypogaea'' and ''E. procumbens'', resulting from a common speciation event. However, the

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

association between the three species remains relatively unreliable, with values of only 53/.66 attributed to the linkage. ''Euphorbia flanaganii'' is in subgenus Athymalus, which comprises 150 species.

Description

It is an agglomerated,

thorn Thorn(s) or The Thorn(s) may refer to: Botany * Thorns, spines, and prickles, sharp structures on plants * ''Crataegus monogyna'', or common hawthorn, a plant species Comics and literature * Rose and Thorn, the two personalities of two DC Com ...

y, succulent plant with snake-like branches that has a swollen underground stem. It is a dwarf shrub with a size of 0.02 to 0.05 m in height that is found at an altitude of 30 to 185 meters. Leaves are rather small, only 10 mm long and 1 mm broad. Its branches grow horizontally, up to 400 mm in diameter. It has inflorescence in

cyathium A cyathium (plural: cyathia) is one of the specialised pseudanthia ("false flowers") forming the inflorescence of plants in the genus ''Euphorbia'' (Euphorbiaceae). A cyathium consists of: * Five (rarely four) bracteoles. These are small, uni ...

with a single, 4 mm long flower per flower stalk that bloom in late summer and autumn. It has photosynthetic modified stems that lack, or have delayed development of,

periderm Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines, and shrubs. Bark refers to all the tissues outside the vascular cambium and is a nontechnical term. It overlays the wood and consist ...

. Careful observation of ''E. flanaganii'' specimens also reveals modified, needle-like leaves, radial geometric symmetry, and a seemingly tuberous above ground root structure.

Distribution

Species within Athymalus, including ''E. flanaganii'', are found only in arid regions such as the Arabian Peninsula, the Canary Islands,

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

, and

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...

Evolution

The historical and modern day geographical home of the subgenus, and the diversity level among species in the same region, suggest species in Athymalus are a lineage of early

divergence In vector calculus, divergence is a vector operator that operates on a vector field, producing a scalar field giving the quantity of the vector field's source at each point. More technically, the divergence represents the volume density of t ...

. A large speciation event of ''Euphorbia'' is believed to have occurred over the course of 3 million to 10 million years ago, due to a significant change in climate, in what are now considered to be modern arid regions; the Athymalus subgenus is believed to have evolved during this period. Given the present body of knowledge that pertains to other Euphorbia species found in the same regions as ''E. flanaganii'', and historical evolutionary events, it is highly likely that ''E. flanaganii'' is roughly 3–10 million years old as well.

References

{{Taxonbar, from=Q8960510 flanaganii Flora of Madagascar Flora of the Canary Islands Flora of the Arabian Peninsula Flora of South Africa Garden plants of Southern Africa Taxa named by N. E. Brown