Scleria gaertneri Raddi

Global description

Scleria gaertneri is a large rhizomatous vivacious sedge, with a generally solitary culm. The culm is triangular in cross-section, slender, and a little scabrous at the angles. The sheath is narrowly tri- winged. The ligule, opposite the blade, is broadly triangular. The leaf blade is narrowly linear, W-shaped in cross-section, abruptly attenuated at the apex. The inflorescence is a fairly narrow panicle with 3-7 short main branches. Spikelets are unisexuals. The female spikelet is globose with 3 broadly oval glumes, mostly brown to dark purple, acuminate at the apex, the tip often curved. The achene is globose and smooth, with a very short tip, pearly grey to dark purple, very visible between the last glumes.

General habit

Scleria gaertneri is a tall, robust sedge, usually growing as a single axis from a huge creeping rhizome, sometimes in clumps of 2 or 3. It is 0.3 to 1 m high.

Underground system

Robust creeping rhizome becoming woody, 4-7 mm in diameter and covered with purple fibrous scales. Fasciculate fibrous roots from the rhizome.

Culm

The culm is mostly single, upright, triangular in cross-section, rather spindly. It is 30 to 100 cm high and 2 to 5 mm in diameter. The angles are finely scabrous.

Leaf

The leaves are simple, alternate in tristically arranged. The basal leaves are reduced to a sheath narrowly winged at the angles, they are 8 to 13 cm long, without any blade. They can be green or dark purple. The upper leaves have a sheath that is triangular in cross-section and narrowly winged at the angles. At the apex of the sheath and opposite the blade is a triangular ligule 3-9 mm high, cartilaginous, hairy at the upper margin and green or purple-brown in colour. The blades of successive leaves are spaced apart. The leaf blade is linear, 15-30 cm long and 7-12 mm wide. The section is strongly folded in an inverted W-shape. The apex is abruptly attenuated into a sharp wedge, the base is gradually attenuated to the width of the sheath. Both sides are glabrous, the margin scabrous.

Inflorescence

The inflorescence is a narrow panicle, 5-15 cm long, sparsely branched with 2-7 short branches, which are themselves rarely or very sparsely branched. They are greenish, brown, reddish brown or dark purple.

Spikelet

Spikelets are unisexuals. The female spikelet is short-stalked and globose, 2 to 3 mm in diameter. It consists of 3 oval, orbicular glumes, 2.5 to 3.5 mm long and wide, with a median keel that ends in a point often curved outwards. The glumes are generally dark purple in colour. The glumes are widely spread, leaving the upper half of the achene clearly visible. The male spikelet is often associated with a female spikelet, it is longer pedunculated, narrow and fusiform, 2 mm long and 0.5 mm in diameter, composed of 3 narrow lanceolate glumes. It contains a single stamen which protrudes well above the top of the spikelet.

Fruit

The fruit is a globular achene, 1.5 to 2.2 mm in diameter, white, grey, brown to dark purple, smooth, with a very short flattened tip. At the base of the achene is a three-lobed disc with a ciliated margin.

Origin

Scleria gaertneri is native to tropical America, the Caribbean, West and Central Africa and certain islands in the Indian Ocean (Madagascar, Reunion, Mauritius, Seychelles).

https://www.gbif.org/species/6311944