THE WEED ISSUE - SCOTCH THISTLE
Russell is as concerned as you are over the spread of weeds in our environment
Farmers and other land managers do their utmost to reduce the impact of weeds on their properties. Available data estimates a cost to agriculture around $4b per annum across Australia. (1) However, the impact on other land and natural habitats is no less a problem - for example, roadside vegetation.
Information you are probably aware of: (Courtesy Parks Victoria)
SCOTCH THISTLE
Alternative Name: Cotton thistle
Famikly Name: Asteraceae
Flowers: Flowerheads made up of many small flowers(florets), heads 2-6cm wide including spiny bracts, heads solitary or in groups.
Description: Erect biennial thistle to 2m high. Stems winged, woolly or cobwebby. Leaves woolly hairy to scattered hairy; basal leaves toothed, to 40cm long and to 25cm wide, withering in mature plants; stem leaves toothed, smaller with base of leaf extending down stems as wings. Seeds 4-ribbed, ovoid to 0.5cm long, grey with darker mottling; topped by minutely barbed bristles to 0.9cm long.
Dispersal: Spread by seed.
Notes: Germinates in Autumn; may remain as a rosette over the first summer. Weed of pasture, also extending over much of non-arid south eastern Australia.
Reference: Noxious weeds of Australia. W.Parsons and E. Cuthbertson, 1992, pages 216 - 218.
(1) http://www.weeds.gov.au/weeds/why/impact.html
LINK:
http://www.weeds.org.au/cgi-bin/weedident.cgi?tpl=plant.tpl&state=&s=®ion=all&card=H21
| 
