''Geissorhiza melanthera'' is a small

perennial plant 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 ...

of 14–18 cm high that is assigned to the family

Iridaceae Iridaceae is a family of plants in order Asparagales, taking its name from the irises, meaning rainbow, referring to its many colours. There are 66 accepted genera with a total of c. 2244 species worldwide (Christenhusz & Byng 2016). It include ...

. It survives the dry southern summer through storage of its

resources Resource refers to all the materials available in our environment which are technologically accessible, economically feasible and culturally sustainable and help us to satisfy our needs and wants. Resources can broadly be classified upon their a ...

in a

corm A corm, bulbo-tuber, or bulbotuber is a short, vertical, swollen underground plant stem that serves as a storage organ that some plants use to survive winter or other adverse conditions such as summer drought and heat (perennation). The word ' ...

. The stem carries two or three erect, sticky leaves of up to 18 cm (7 in) long, H-shaped in cross-section. This species blooms with six to twelve

bilaterally symmetrical Symmetry in biology refers to the symmetry observed in organisms, including plants, animals, fungi, and bacteria. External symmetry can be easily seen by just looking at an organism. For example, take the face of a human being which has a pla ...

flowers, in a spike. Sometimes the spike has one side branch with fewer flowers. Each flower has six pale beige

perianth The perianth (perigonium, perigon or perigone in monocots) is the non-reproductive part of the flower, and structure that forms an envelope surrounding the sexual organs, consisting of the calyx (sepals) and the corolla (petals) or tepals when ...

lobes, a purple-red ring around a purple red tube and three blackish

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s. Each flower is subtended by two 1.25–2.25 cm long green bracts. This species flowers from the end of September till mid October. It is an

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

of the western slopes of the

Piketberg Piketberg (also sometimes spelt Piquetberg in the past) is a town in the Western Cape, South Africa, located about 80 km east of Saldanha Bay. The original spelling of the name was "Piquetberg". The town is in the foothills of the Piketberg mounta ...

mountains in the

Western Cape The Western Cape is a province of South Africa, situated on the south-western coast of the country. It is the fourth largest of the nine provinces with an area of , and the third most populous, with an estimated 7 million inhabitants in 2020 ...

province of South Africa.

Taxonomy

The species was described in a publication in 2013 by South African botanists

Peter Goldblatt Peter Goldblatt (born 1943) is a South African botanist, working principally in the United States. Life Goldblatt was born in Johannesburg, South Africa on October 8, 1943. His undergraduate studies (B.Sc.) were undertaken at the University ...

and John Manning. It belongs to the

section Section, Sectioning or Sectioned may refer to: Arts, entertainment and media * Section (music), a complete, but not independent, musical idea * Section (typography), a subdivision, especially of a chapter, in books and documents ** Section sign ...

''Engysiphon''.

Ecology

The bee fly ''Megapalpus capensis'' is the only species that has been observed visiting the flowers of ''Geissorhiza melanthera''. Remarkably, ''G. melanthera'' is the only Iridaceae known to be pollinated by a bee fly. ''Megapalpus capensis'' is also known to visit several ''

Pelargonium ''Pelargonium'' () is a genus of flowering plants that includes about 280 species of perennials, succulents, and shrubs, commonly called geraniums, pelargoniums, or storksbills. '' Geranium'' is also the botanical name and common name of a separ ...

'' species, all of which have white, cream or pale pink petals with blackish markings and mostly dark anthers. ''

Gorteria diffusa ''Gorteria diffusa'' is a highly Genetic variability, variable, small Annual plant, annual herbaceous plant or rarely a subshrub, shrublet that is assigned to the Asteraceae, daisy family (Compositae or Asteraceae). Like in almost all Asteraceae, ...

'' that is visited by the same bee fly species often has dark spots on some or all of its yellow or orange ray florets, that closely mimic the bee fly's appearance. The species grows in deep sandy soils, on gentle slopes facing south, in an ecosystem called Leipoldtville Sand

Fynbos Fynbos (; meaning fine plants) is a small belt of natural shrubland or heathland vegetation located in the Western Cape and Eastern Cape provinces of South Africa. This area is predominantly coastal and mountainous, with a Mediterranean clim ...

Conservation

''Geissorhiza melanthera'' is known from only two locations, one of which has been requested to allow to reclaim it for the cultivation of

rooibos Rooibos ( ; , meaning "red bush"), or ''Aspalathus linearis'', is a broom (shrub), broom-like member of the plant family Fabaceae that grows in South Africa's fynbos biome. The leaves are used to make a herbal tea that is called rooibos (esp ...

. It is therefore considered endangered.

References

{{Taxonbar, from=Q42560885 Plants described in 2013 Endemic flora of the Cape Provinces

melanthera ''Melanthera'' (common name: squarestem), is a genus of perennial flowering plants in the family Asteraceae, native to North and South America, as well as Africa, Asia and Oceania, including Hawaii. The most common species of this genus is ''Me ...

Taxa named by Peter Goldblatt Taxa named by John Charles Manning