Osmadenia
Encyclopedia
Osmadenia is a monotypic genus
of flowering plants in the daisy family
containing the single species Osmadenia tenella, which is known by the common name false rosinweed. It is native to the hills and canyons of southern California
and Baja California
, where it is an uncommon member of the flora in local habitat such as chaparral
. It is a hairy, glandular, aromatic annual herb producing an erect stem approaching 40 centimeters in maximum height with threadlike branches. The linear leaves are alternately arranged, the largest low on the plant measuring up to 5 centimeters. The inflorescence
is a cyme of several flower heads
. Each head has 3 to 5 three-lobed ray florets which are white or pink-tinged and often have a pink spot, and several narrower disc florets. The fruit is an achene
; those arising from disc florets have pappi
.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of flowering plants in the daisy family
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...
containing the single species Osmadenia tenella, which is known by the common name false rosinweed. It is native to the hills and canyons of southern 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...
and Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
, where it is an uncommon member of the flora in local habitat such as chaparral
Chaparral
Chaparral is a shrubland or heathland plant community found primarily in the U.S. state of California and in the northern portion of the Baja California peninsula, Mexico...
. It is a hairy, glandular, aromatic annual herb producing an erect stem approaching 40 centimeters in maximum height with threadlike branches. The linear leaves are alternately arranged, the largest low on the plant measuring up to 5 centimeters. 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 cyme of several 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 3 to 5 three-lobed ray florets which are white or pink-tinged and often have a pink spot, and several narrower disc florets. The fruit is an achene
Achene
An achene is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate and indehiscent...
; those arising from disc florets have pappi
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...
.