Senecio aronicoides
Encyclopedia
Senecio aronicoides is a species of flowering plant in the aster family
known by the common name rayless ragwort. It is native to Oregon
and northern and central California
, where it can be found in the woodlands and forests of mountains and foothills, often in relatively dry habitat. It is a biennial or perennial herb growing up to about 90 centimeters tall from a fleshy root attached to a buttonlike caudex
. The plant is often slightly woolly or cobwebby in texture. The leaves have lance-shaped to oval blades measuring up to 20 centimeters long, the largest ones lower on the stem. The inflorescence
is a corymb
which is flat and spreading, often resembling an umbel
. The flower head
s are cups lined with black- or green-tipped phyllaries
and filled with many gold disc florets. There are usually no ray florets but one or two occasionally emerge from a head. The fruit is a hairless achene
tipped with a pappus
of long, white bristles.
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 rayless ragwort. It is native to 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...
and northern and central California
California
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...
, where it can be found in the woodlands and forests of mountains and foothills, often in relatively dry habitat. It is a biennial or perennial herb growing up to about 90 centimeters tall from a fleshy root attached to a buttonlike caudex
Caudex
A caudex is a form of stem morphology appearing as a thickened, short, perennial stem that is either underground or near ground level . It may be swollen for the purpose of water storage, especially in xerophytes...
. The plant is often slightly woolly or cobwebby in texture. The leaves have lance-shaped to oval blades measuring up to 20 centimeters long, the largest ones lower on the stem. 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...
is a corymb
Panicle
A panicle is a compound raceme, a loose, much-branched indeterminate inflorescence with pedicellate flowers attached along the secondary branches; in other words, a branched cluster of flowers in which the branches are racemes....
which is flat and spreading, often resembling an umbel
Umbel
An umbel is an inflorescence which consists of a number of short flower stalks which are equal in length and spread from a common point, somewhat like umbrella ribs....
. The flower head
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
s are cups lined with black- or green-tipped phyllaries
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
and filled with many gold disc florets. There are usually no ray florets but one or two occasionally emerge from a head. The fruit is a hairless achene
Achene
An achene is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate and indehiscent...
tipped with a pappus
Pappus (flower structure)
The pappus is the modified calyx, the part of an individual disk, ray or ligule floret surrounding the base of the corolla, in flower heads of the plant family Asteraceae. The pappus may be composed of bristles , awns, scales, or may be absent. In some species, the pappus is too small to see...
of long, white bristles.