Willkommia

Willkommia
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Monocots
(unranked): Commelinids
Order: Poales
Family: Poaceae
Genus: Willkommia
Hack.
Type species
Willkommia sarmentosa
Hack.
Synonyms[1]

Willbleibia Herter

Willkommia is a genus of plants in the grass family.[2][3] The genus has a disjunct distribution, with species native to Southern Africa, South America, and the USA.[1]

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

Accepted Species[1][4][5]
  1. Willkommia annua Hack. - Angola, Namibia
  2. Willkommia newtonii Hack. - Angola, Namibia
  3. Willkommia sarmentosa Hack. - Angola, Namibia, Zambia, Zimbabwe, Botswana, Cape Province, KwaZulu-Natal
  4. Willkommia texana Hitchc. - USA (Texas, Oklahoma),[6] Argentina, Uruguay[7]


References

  1. 1 2 3 Kew World Checklist of Selected Plant Families
  2. ↑ Hackel, Eduard. 1888. Verhandlungen des Botanischen Vereins für die Provinz Brandenburg und die Angrenzenden Länder 30: 145-146 descriptions in Latin, locality information in German
  3. ↑ Tropicos, Willkommia Hack.
  4. ↑ Grassbase - The World Online Grass Flora
  5. ↑ Clayton, W.D.; Vorontsova, M.S.; Harman, K.T.; Williamson, H. "Willkomias". GrassBase - The Online World Grass Flora. Royal Botanic Gardens, Kew.
  6. ↑ Biota of North America Program, 2013 distribution map
  7. ↑ Parodi, Lorenzo Raimundo. 1925. Physis. Revista de la Sociedad Argentina de Ciencias Naturales 8: 78
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