Nassella, or needlegrass, is a New World genus of over 100 perennial bunchgrasses found from North America through South America. The Latin word nassa refers to "a basket with a narrow neck".[1] It is usually considered segregate from the genus Stipa and includes many New World species formerly classified in that genus.[2] As of 2011, The Jepson Manual includes Nassella within Stipa.[3]

Nassella
Nassella tenuissima
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Clade: Commelinids
Order: Poales
Family: Poaceae
Subfamily: Pooideae
Supertribe: Stipodae
Tribe: Stipeae
Genus: Nassella
(Trin.) É.Desv. (1854)
Type species
Nassella pungens
Species

Many, see text

Nasella is characterized by strongly overlapping lemma margins and reduced, veinless paleae. The lemma tips are fused into the "crown", a short membrane that surrounds the base of the lemma. The rim of the crown usually has hairs.

Many species form both cross-pollinating and self-pollinating florets in the terminal panicle. The self-pollinating florets have 1–3 small anthers; the cross-pollinating florets have 3 longer anthers. Some species have self-pollinating inflorescences hidden in their basal leaf sheaths. These hidden inflorescences lack glumes and usually lack awns.

Some species (especially Nassella neesiana and Nassella tenuissima) are considered invasive pests, as the grass is not properly digested by ruminants.[4][5][6]

Diversity

edit

As of 2001, there were about 116 species in this genus.[7]

California species

edit
  • Nassella pulchra – purple needlegrass; currently reclassified as Stipa pulchra.
  • Nassella lepida – foothill needlegrass; currently reclassified as Stipa lepida.
  • Nassella cernua – nodding needlegrass; currently reclassified as Stipa cernua.

Horticultural species

edit
  • An attractive, drought-tolerant bunchgrass with fine leaves and a narrow inflorescence that sways gracefully in the wind. However, it readily escapes from cultivation and takes hold in disturbed areas, natural areas, and in sidewalk cracks, driveways, and tree wells. It is an invasive species in California and Oregon.

Other species

edit

References

edit
  1. ^ Nassella. The Jepson Manual.
  2. ^ Barkworth, M. E. Nassella E.Desv. Archived 2006-12-05 at the Wayback Machine Stipeae Pages. Intermountain Herbarium, Utah State University. June 13, 2003.
  3. ^ Stipa pulchra. The Jepson Manual.
  4. ^ "GISD".
  5. ^ "GISD".
  6. ^ Bourdôt, Graeme W.; Lamoureaux, Shona L.; Watt, Michael S.; Manning, Lucy K.; Kriticos, Darren J. (2012). "The potential global distribution of the invasive weed Nassella neesiana under current and future climates". Biological Invasions. 14 (8): 1545–1556. Bibcode:2012BiInv..14.1545B. doi:10.1007/s10530-010-9905-6. S2CID 14852104 – via ResearchGate.
  7. ^ Barkworth, M. E. and M. A. Torres. (2001). Distribution and diagnostic characters of Nassella (Poaceae: Stipeae). Taxon 50(2) Golden Jubilee Part 4, 439–68.
  8. ^ "History and Culture: State Insignia", California State Library, December 8, 2006.
edit