Hemizonia congesta
Encyclopedia
Hemizonia congesta is a species of flowering plant in the daisy family
known by the common name hayfield tarweed.
and Oregon
, where it is a common member of the flora in a number of habitats, particularly grassland
s and fields.
. Most of the long, narrow, pointed leaves are located on the lower portion of the stem below the branching.
The inflorescence
s are covered in glandular hairs and hold daisylike flower heads
. Each head has a center of yellowish dark-tipped disc florets and a fringe of bright yellow to white ray florets, often with purplish striping on the undersides. The ray florets are toothed or lobed on the tips, with the middle tooth thinner than the others.
There are many subspecies which can vary in appearance.
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...
known by the common name hayfield tarweed.
Range
Hemizonia congesta is native to CaliforniaCalifornia
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
and Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
, where it is a common member of the flora in a number of habitats, particularly grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
s and fields.
Description
Hemizonia congesta is a spindly, thin-stemmed annual herb growing erect to 10 to 80 centimeters in height. Like other tarweeds the stem and foliage are glandular and have an odor reminiscent of tarTar
Tar is modified pitch produced primarily from the wood and roots of pine by destructive distillation under pyrolysis. Production and trade in tar was a major contributor in the economies of Northern Europe and Colonial America. Its main use was in preserving wooden vessels against rot. The largest...
. Most of the long, narrow, pointed leaves are located on the lower portion of the stem below the branching.
The inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
s are covered in glandular hairs and hold daisylike flower heads
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
. Each head has a center of yellowish dark-tipped disc florets and a fringe of bright yellow to white ray florets, often with purplish striping on the undersides. The ray florets are toothed or lobed on the tips, with the middle tooth thinner than the others.
There are many subspecies which can vary in appearance.