Kingdom Plantae Family Poaceae Higher classification Grasses | Order Poales Scientific name Willkommia Rank Genus | |
Similar Grasses, Triraphis, Brachyachne | ||
Willkommia is a genus of plants in the grass family. The genus has a disjunct distribution, with species native to Southern Africa, South America, and the United States.
Contents
Description
Annual (1), or perennial (3). Stolons absent (1), or present (3). Culms decumbent (1/1); 20–40–60 cm long; firm (3), or wiry (1); rooting from lower nodes (1/1). Ligule a ciliate membrane (1), or a fringe of hairs (3). Leaf-blades stiff (1), or firm (3). Leaf-blade margins cartilaginous (2/2).
Inflorescence composed of racemes. Racemes borne along a central axis; unilateral. Rhachis flattened (2), or angular (2). Spikelet packing adaxial; 2 -rowed (1/1). Spikelets appressed (1), or ascending (3); solitary. Fertile spikelets sessile.
Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; 2.5–3.962–5 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus brief (1), or elongated (3); pubescent (3/3); obtuse (1), or pungent (3).
Glumes lower persistent, upper deciduous; reaching apex of florets (2), or exceeding apex of florets (2); firmer than fertile lemma. Lower glume lanceolate (2), or elliptic (1), or oblong (1); 0.5–0.6625–0.75 length of upper glume; hyaline; without keels; 0 -veined. Lower glume lateral veins absent. Lower glume surface without pits. Lower glume apex obtuse (2), or acute (2). Upper glume elliptic; 1–1.1–1.3 length of adjacent fertile lemma; hyaline (1), or chartaceous (3); without keels; 1 -veined. Upper glume surface smooth (2), or asperulous (2). Upper glume apex obtuse (1), or acute (3).
Fertile lemma elliptic; membranous; without keel; wingless; 3 -veined. Lemma surface unwrinkled; without grooves; glabrous (2), or pubescent (2), or pilose (1). Lemma margins eciliate (1), or ciliate (3). Lemma apex obtuse (1), or acute (3); mucronate (1), or awned (3); 1 -awned (3/3). Palea keels eciliate (3), or ciliate (1). Palea surface glabrous (3), or pilose (1).
Caryopsis with adherent pericarp; ellipsoid (1/1).
Species
- Willkommia annua Hack. - Angola, Namibia
- Willkommia newtonii Hack. - Angola, Namibia
- Willkommia sarmentosa Hack. - Angola, Namibia, Zambia, Zimbabwe, Botswana, Cape Province, KwaZulu-Natal
- Willkommia texana Hitchc. - United States (Texas, Oklahoma), Argentina, Uruguay