Erigeron bonariensis

Description

Erigeron bonariensis grows up to 75 cm in height and its leaves are covered with stiff hairs, including long hairs near the apex of the bracts. Its flower heads have white ray florets and yellow disc florets. It can easily be confused with Erigeron canadensis, which grows taller, and E. sumatrensis.

It flowers in August and continues fruiting until the first frosts. It is instantly recognisable by its blue-green foliage, very narrow, undulate stem-leaves, and purple-tipped involucral bracts. It reproduces only by seed, which are easily blown and spread by wind.

Distribution and habitat

Erigeron bonariensis is found throughout the tropics and subtropics as a pioneer plant; its precise origin is unknown, but most likely it stems from Central America or South America. It has become naturalized in many other regions, including North America, Europe and Australia.

E. bonariensis is a rare alien in southeastern England, found along walls and in cracks in pavements and concrete driveways. It is widespread throughout Australia, where it thrives on roadsides, fallows, pastures, gardens, lawns, footpaths, parks, riparian vegetation, forest and wetland perimeters, waste dumps and disturbed grounds.

Photographic Description

Dry Summer Form

• The following are bright dry summer 1st-year forms; in contrast to shady damp winter forms that follow. Erigeron bonariensis from Antalya by D Merrick 11.jpg|General view Erigeron bonariensis from Antalya by D Merrick 09.jpg|Top-heavy greyish gangly look with initial central inflorescence subsequently overtopped by some side ones Erigeron bonariensis from Antalya by D Merrick 01.jpg|Broad heads (may be narrower especially in winter) usually with reddened tips Erigeron bonariensis from Antalya by D Merrick 02.jpg|Head close up Erigeron bonariensis from Antalya by D Merrick 05.jpg|Leaf narrow showing hairs Erigeron bonariensis from Antalya by D Merrick 07.jpg|Leaf surface hairs (similar underside), sometimes poorly hairy Erigeron bonariensis from Antalya by D Merrick 06.jpg|Hairs at leaf tip Erigeron bonariensis from Antalya by D Merrick 08.jpg|Leaf base hairs (a few long ones usually present) and underside hairs Erigeron bonariensis from Antalya by D Merrick 10.jpg|Stem leaves of robust stems multi-lengthed, grey (sometimes green)

Winter, Damp, Shady, Biennial Forms

• Showing diffusely branched or strangled appearances with small flower heads Erigeron bonariensis from Antalya by D Merrick 101.jpg|Winter form near water in the open

Erigeron bonariensis from Antalya by D Merrick 102.jpg|Strangled winter form in the open

Erigeron bonariensis from Antalya by D Merrick 103.jpg|Winter form in damp shade

Erigeron bonariensis from Antalya by D Merrick 108.jpg|From a biennial form

Erigeron bonariensis from Antalya by D Merrick 03.jpg|May have particularly reddened heads

Other photos

Erigeron bonariensis1.jpg|Erigeron bonariensis growing as a weed on a building in New Delhi, India Conyza bonariensis stem1 & sumatrensis stems (12402804144).jpg|Stiff hairs cover the plant. Starr-170304-0326-Conyza bonariensis-leaves-Lower Waiohuli Trail Polipoli-Maui (33382595585).jpg|Basal rosette leaves, before plant matures and flowers, Maui, Hawaii Conyza bonariensis.jpg|Foliage becomes grey-green in dry-summer regions, such as Israel Starr-170225-0052-Conyza bonariensis-flowers-Lower Waiohuli Trail Polipoli-Maui (32566847513).jpg|White ray flowers and yellow disc flowers in fully "open" flower heads, Maui, Hawaii Erigeron bonariensis (Familyː Asteraceae) - weed.jpg|Flower heads are followed by seeds, which are easily carried by the wind.

References

References

1. [http://www.tropicos.org/Name/2702433 Tropicos, Erigeron bonariensis L.]
2. {{GRIN. ''Conyza bonariensis''. 104170
3. [http://www.iewf.org/weedid/Conyza_bonariensis.htm ''Conyza bonariensis''], International Environmental Weed Foundation
4. [http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=242422264 Flora of China, ''Erigeron bonariensis'' L. 1753. 香丝草 xiang si cao ]
5. [http://www.maltawildplants.com/ASTR/Conyza_bonariensis.html Comprehensive profile for ''Conyza bonariensis''] {{Webarchive. link. (2006-11-10 , Malta Wild Plants)
6. [http://www.flowersinisrael.com/Conyzabonariensis_page.htm ''Conyza bonariensis''], Flowers in Israel
7. [http://luirig.altervista.org/flora/taxa/index1.php?scientific-name=erigeron+bonariensis Altervista Flora Italiana, Cespica di Buenos Aires, ''Erigeron bonariensis'' L.] includes photos and European distribution map
8. [http://vro.agriculture.vic.gov.au/dpi/vro/vrosite.nsf/pages/sip_tall_fleabane] Tall Fleabane by Agriculture of Victoria
9. [https://weeds.brisbane.qld.gov.au/weeds/flaxleaf-fleabane] [[Brisbane City Council]] Weed Identification Tool