Rhynchospora gracillima is a widespread species of sedge.
Description
Rhynchospora gracillima is an annual or short-lived perennial sedge that may grow to be 20–60 cm (0.66–1.97 ft) tall. The 3-angled culms are smooth and densely tufted. The leaves are shorter than the culms and have stiff hairs. They are up to 1 mm (0.039 in) wide and tips are rough. The bracts have longitudinal grooves and sheath the leaves and culms.
The inflorescences are loosely branched, made of one to three clusters, with the outer flowers borne on longer stems than the central ones. The stems are up to 4 cm (1.6 in) long. The rays are smooth and often curve upwards, supported by bristled bractlets. The solitary spikelets are narrow, elongated ovals, containing three or four flowers with long stems. There are seven or eight pale brownish glumes with purplish lines that overlap and spiral. Each floret has two stamens and two well-developed style branches.
The morphology of the spikelets has been studied in more detail in Rhynchospora gracillima subsp. subquadrata. While there are usually seven or eight glumes, some specimens may have as many as eleven. The central glumes (glumes four to nine) are the largest and best developed, noticeably spiraled with enlarged, curved, and flattened internodes to accommodate the seeds. Glumes five to nine usually mature to form seeds, with glumes five, ten, and eleven sometimes forming seeds. Glumes one through four are always infertile.
The fruit is a greyish white nutlet that is biconvex with deep, wavy ridges.
Distribution and habitat
This species has two subspecies:
- Rhynchospora gracillima subsp. gracillima is found growing from Asia to Oceania.
- Rhynchospora gracillima subsp. subquadrata grows in Africa, Madagascar, and Mauritius.
It grows in moist places, grassy slopes, and forests. While mostly found at lower altitudes, it has been recorded at elevations up to 1,200 m (3,900 ft) above sea level.
Countries where Rhynchospora gracillima is known to grow include Australia, Benin, Burkina Faso, Cameroon, Central African Republic, China, Congo, Democratic Republic of the Congo, Eswatini, Ethiopia, Gabon, Ghana, Guinea, India, Indonesia, Ivory Coast, Liberia, Madagascar, Mali, Nigeria, Papua New Guinea, Senegal, South Africa, Sri Lanka, Tanzania, Thailand, Togo, Uganda, Zambia, and Zimbabwe. It is also suspected to occur in Angola, Burundi, Chad, Equatorial Guinea, Guinea-Bissau, Malawi, Mozambique, Rwanda, Sierra Leone, South Sudan, and The Gambia.
Conservation
This species is considered to be of least concern by the IUCN. It is widely distributed, and its population is stable.