''Romulea sabulosa'' is a perennial

geophyte A storage organ is a part of a plant specifically modified for storage of energy (generally in the form of carbohydrates) or water. Storage organs often grow underground, where they are better protected from attack by herbivores. Plants that have ...

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 has a few grooved thread-like leaves, and relatively large burgundy red

trimerous Merosity (from the greek "méros," which means "having parts") refers to the number of component parts in a distinct whorl of a plant structure. The term is most commonly used in the context of a flower where it refers to the number of sepals in ...

flowers, reminiscent of crocus flowers, with yellow to light greenish with black markings and stamens with light green free filaments. It only occurs on sandy clay on

renosterveld Renosterveld is a term used for one of the major plant communities and vegetation types of the Cape Floristic Region (Cape Floral Kingdom) which is located in southwestern and southeastern South Africa, in southernmost Africa. It is an ecoregion ...

west of

Nieuwoudtville Nieuwoudtville is a town in Namakwa District Municipality in the Northern Cape province of South Africa. The town lies on the Bokkeveld Escarpment, and was established in 1897. The Nieuwoudtville Falls on the Doring River are located a few kil ...

in the Northern Cape province South Africa. It is called satynblom in

Afrikaans Afrikaans (, ) is a West Germanic language that evolved in the Dutch Cape Colony from the Dutch vernacular of Holland proper (i.e., the Hollandic dialect) used by Dutch, French, and German settlers and their enslaved people. Afrikaans gra ...

Description

''Romulea sabulosa'' is a low to medium height

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 wid ...

of high, that has a subterranean stem, that develops from 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 ' ...

with a rounded base that is wrapped in a brown tunic with curved pointed teeth. The three to five thread-like leaves emerge directly from the soil, are about in diameter and have four grooves along their lengths. Over a season, one to four flowers may develop per corm. Each flower is subtended by two bracts that have a transparent, often brownish margin. The outer bract mostly has one keel on its upper surface and the transparent margin is narrow, while the inner bract has two keels and the papery margin is wider. The scentless,

flower itself is dark red, sometimes pink, and has black blotches in a creamy green cup. The

tepal A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...

s that are fused in a tube at their base are inverted egg-shaped with a slightly indented tip 2½–4 cm (1–1.6 in) long. The outer tepals have a light yellow feathered stripes. The stamens consist of long free filaments topped by anthers of long. The stalk supporting the ripe fruit remains more or less erect. ''Romulea sabulosa'' flowers can be found from July till September.

Differences with related species

''Romulea sabulosa'' has slender, tapering, mostly pale green filaments, while '' R. monadelpha'' as short, oblong, black filaments that are pressed together or fused. The flower stalk of ''R. sabulosa'' is slender, more or less circular in cross section and does not curve when the fruit is ripe, but in ''R. monadelpha'' the flower stem is stout and has one flattened side while it spreads out when the fruit is ripe. The species occur in the same area near Nieuwoudtville, but have a different habitat: ''R. sabulosa'' occurs only on a light sandy clay known as

tillite image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...

, while ''R. monadelpha'' grows on heavy

dolerite Diabase (), also called dolerite () or microgabbro, is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine-grain ...

clay.

Taxonomy

''Romulea sabulosa'' was described by the German botanist

Rudolf Schlechter Friedrich Richard Rudolf Schlechter (16 October 1872 – 16 November 1925) was a German taxonomist, botanist, and author of several works on orchids. He went on botanical expeditions in Africa, Indonesia, New Guinea, South and Central America and ...

in 1907.

Distribution, habitat and ecology

''Romulea sabulosa'' is limited to the Bokkeveld plateau along the

escarpment An escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations. The terms ''scarp'' and ''scarp face'' are often used interchangeably with ''esca ...

west of Nieuwoudtville where it grows in large swarms on a light sandy clay called

. The species has been observed to be pollinated exclusively by

monkey beetle Monkey beetles are scarab beetles, a group of several genera within the tribe Hopliini. The placement of this tribe within the family Scarabaeidae is uncertain between Melolonthinae and Rutelinae. Many species visit flowers for pollen and necta ...

Conservation

This species has a very small range of only , and is known from just five separate locations. Over the last half century about 80% of its habitat has been lost to wheat cultivation, but the decline has been stopped for the moment. Further development into crop land and invasive alien grasses may endanger the species in the future. It therefore is considered vulnerable.

References

{{Taxonbar, from=Q15582880 Endemic flora of South Africa sabulosa Plants described in 1907