TAXONOMY
Hawkweeds are
in the Tribe Lactuceae of the Family Asteraceae,
having all
strap-shaped (ligulate) flowers and a milky latex in stems and
leaves.
The genus
Hieracium is divided into 3 subgenera. Subgenus Chionoracium
(formerly subgenus Stenotheca) represents the
± 20
native species in
North America Subgenus Hieracium
occurs in both North America and Europe. Two native species occur
in the PNW (Native Table); six
species from
central and eastern Europe
also occur in the region; including smooth hawkweed, common
hawkweed, European hawkweed, polar hawkweed, spotted hawkweed, and
wall hawkweed (Non- Native
Table).
Subgenus Pilosella, entirely European in origin,
represents most of the invasive species in the PNW. The eight
known
invasive species in
subgenus Pilosella include meadow hawkweed, orange hawkweed,
mouse-ear hawkweed, whiplash hawkweed, kingdevil hawkweed,
queendevil hawkweed, and tall hawkweed (Non-
Native Table). A new
species, yellowdevil hawkweed, was identified from southeastern
British Columbia in 2001. This was the first report of this species
in North America (Wilson et al. 2006.
Can. J. Botany 84: 133–142).
|
