T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Erechtites hieraciifolia (American burnweed)

Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Asterales
Family: Asteraceae
Tribe: Senecioneae
Genus: Erechtites
Species: E. hieraciifolia
Binomial name: Erechtites hieraciifolia
Common name: American fireweed, American burnweed, Pilewort, Burnweed

Erechtites hieraciifolia is an aggressive, erect, annual weed that grows up to 2 m tall. It is native to North and South America. It is common in wet places in the north of the North Island of New Zealand: Bay of Plenty, Waikato, Coromandel Peninsula and Auckland. This species benefits from fire and is often one of the earliest pioneer species of areas that have recently burned, hence some of its common names. It prefers moist sites where it can be is aggressive. It can handle gravely soil and some degree of dry conditions. It also grows well in urban areas and around humans.

Erechtites hieraciifolius is a herbaceous plant with alternate, simple leaves, on thick, green stems. The stems have fine ridges, darker green vertical lines and sparse white hair or they can be hairless. 
The leaves are serrated and range from unlobed to deeply lobed, with the lobe pattern. There are coarse pointed teeth on the lobes. The blade is mostly ovate to lanceolate with lobes.
Flowering occurs during autumn. The flower heads are yellow coloured florets which are followed by a cluster of small, wispy achenes. The flowers are pollinated primarily by wasps and the seeds are wind-dispersed. 
The plant often branches and grows in a clump with multiple stems.
Erechtites species can be identified from the Sonchus species by their hollow stems lacking latex.


Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/