Hawkweed

Hawkweed
Orange Hawkweed (Hieracium aurantiacum)
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Asterales
Family: Asteraceae
Subfamily: Cichorioideae
Tribe: Cichorieae
Genera

Hieracium
Pilosella

Hawkweed refers to any species in the very large genus Hieracium and its segregate genus Pilosella, in the sunflower family (Asteraceae).

They are common perennials, occurring worldwide . They are usually small and weedy. Only a few are ornamental plants. Most are considered to be troublesome weeds.

They grow to 5–100 cm tall, and feature clusters of yellow, orange or red flower heads, similar to dandelions, atop a long, fuzzy stalk.

Hawkweed is a slang name taken from folklore which says that hawks would chew on the plant to improve their eyesight.

Hawkweeds are used as food plants by the larvae of some Lepidoptera species including Autumnal Rustic, Broad-barred White, Dot Moth, Hebrew Character, Large Yellow Underwing, Lime-speck Pug, The Shark, the grass moth Diasemia reticularis, and also by small beetles.

Taxonomy

Few genera are more complex and have given botanists such trouble due to the great number of apomictic species. Through speciation by rapid evolution, polyploidy, and possibly also hybridisation, this variable genus has given rise to thousands of small variations and more than 10,000 microspecies, each with their own taxonomic name, have been described. The database IPNI provides more than 12,000 named taxa for this genus, including subspecies and synonyms, but it is far from complete.

Attempts have been made to break up this genus in Hieracium (sensu stricto; retaining most species) and Pilosella (about 16 species), based on achene characters and the occurrence of stolons.

Species

The list below is a selection of species for which common names are recorded. A more complete list is given in List of Hieracium species.

Hieracium
Pilosella

References