Leaves |
Fine hairs giving a soft texture, particularly to younger leaves Grey-green to dark green Young leaves often purple, especially when growing in sun Leaves often larger, more prominently ribbed |
Largely smooth Yellow-green when growing in sun, dark green in semi-shade Young leaves often red, especially when growing in sun Leaves generally smaller |
Stems | Hairy, grey-green to dark green | Largely smooth, yellow-green |
Flowers | Pale lilac Broader individual flowers Bracts with sharp tips, lax around flower-head
| White Narrower individual flowers Bracts with rounded tips, tight around flower-head
|
Crown | Larger plants have underground ‘corm’ structure
| ‘Corm’ less prominent |
Growth form | Branches more lax | More upright growth form, especially young growth in dense stands |
Ecology | May be more fire resistant, resprouting from crown May be more adapted to tropical conditions
| May be more susceptible to fire. Burning frequently kills large plants May be more cool tolerant (Kriticos et al., 2005)
|
Photographic acknowledgements
All AWA chromolaena biotype photos courtesy of Colin Wilson, except for photo of corm from Joshi (2006). All SA chromolaena biotype photos courtesy of
ARC-PPRI.
References
Kriticos, D. J., Yonow, T. and McFadyen, R. E. (2005) The potential distribution of Chromolaena odorata (Siam weed) in relation to climate. Weed Research 45: 246-254.
Joshi, C. (2006) Mapping cryptic invaders and invasibility of tropical forest ecosystems: Chromolaena odorata in Nepal. Dissertation, International Institute for Geo-information Science & Earth Observation, Enschede, the Netherlands.
Zachariades, C., Day, M.D., Muniappan, R. and Reddy, G.V.P. (2009) Chromolaena odorata (Asteraceae) and its biological control. In: Muniappan, R., Reddy, G.V.P., Raman, A. (Eds.), Biological Control of Tropical Weeds using Arthropods. Cambridge University Press, Cambridge. pp. 130-162.