Gazania linearis explained

Gazania linearis is a species of flowering plant in the family Asteraceae, with thin linear leaves, native to South Africa.

Description

Gazania linearis is a clumping perennial herb. The leaves are usually slender and linear in shape, and are usually simple (but can sometimes also be slightly pinnate). The lower leaf margins are rough and spiny-to-ciliate. The upper leaf surface is dull green while the undersides are white woolly/tomentose. The leaves have long, winged petioles and form basal rosettes at the ground around the short branching stem. (Unlike the type variety of G. linearis, which has linear leaves, the rare variety G. linearis var. ovalis has more oval shaped leaves. It is however only known from a small area near Grahamstown.)[1]

The plant produces large, solitary daisy-like flower-heads that are invariably bright yellow. The ray florets may have dark spots near the bases, curl upwards along their edges, and close at night. The involucre is subcupuliform or obtusely bell-shaped (campanulate) in shape. Both the involucre and scape can be glabrous or setose. There are usually some parietal bracts arranged around the involucre. Of the terminal involucre bracts, the outer row is linear with setose-ciliate margins, while the inner row is acuminate with membranous-entire margins. The fruit is a tiny achene covered in very long hairs several times the length of the fruit body.[2] [3] [4]

Diagnostic characters

Gazania linearis is very similar in its morphology to Gazania krebsiana, Gazania ciliaris, Gazania pectinata, Gazania rigida and others. It is partially distinguished from other Gazania species by a mixture of several characteristics:[5]

Distribution and ecology

Gazania linearis var. linearis (with linear leaves) is indigenous to the southern and eastern parts of South Africa, where it occurs from the Eastern Cape (Humansdorp) in the west, eastwards to KwaZulu-Natal Province.

Gazania linearis var. ovalis (with more oval-shaped leaves) is restricted to a small area near Grahamstown, in the Eastern Cape.[6]

Mixed Gazania cultivars, sometimes identified as G. linearis, have also taken hold as an introduced species in other parts of the world with similar climates, such as in California and New Mexico in the United States; Australia; and New Zealand, where they have been classified as a weed.[2] The plants typically grow on grassy and rocky hillsides.[7] They are also classified as invasive in some areas, including California.[7]

External links

Notes and References

  1. Magee, A.R., Boatwright, J.S. & Mucina, L. (2011). Gazania lanata and G. splendidissima: Two new species of Asteraceae (tribe Arctotideae) from the Greater Capensis, with an updated key for the genus. South African Journal of Botany 77(1):86-93.
  2. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250066797 Flora of North America v 19 p 197
  3. Druce, George Claridge. Report, Botanical Society and Exchange Club of the British Isles 4(suppl. 2): 624. 1916
  4. http://kumbulanursery.co.za/plants/gazania-linearis Kumbula Indigenous Nursery
  5. Magee, A.R., Boatwright, J.S. & Mucina, L. (2011). Gazania lanata and G. splendidissima: Two new species of Asteraceae (tribe Arctotideae) from the Greater Capensis, with an updated key for the genus. South African Journal of Botany 77(1):86-93.
  6. Mucina, L., Howis, S. & Barker, N. (2009). Globally grown, but poorly known: Species limits and biogeography of Gazania Gaertn. (Asteraceae) inferred from chloroplast and nuclear DNA sequence data. Taxon 58:871-882. 10.1002/tax.583015. p.879
  7. Web site: Gazania linearis 'Colorado Gold' . Missouri Botanical Garden. 11 April 2018.