Tetradymia spinosa
Encyclopedia
Tetradymia spinosa is a species of flowering plant in the aster family
known by the common name shortspine horsebrush. It is native to the western United States, especially the basins and plateaus west of the Rocky Mountains
. It grows in sagebrush
, woodlands, and scrub habitat, often among shadscale
in alkaline areas such as playas
. It is a bushy shrub
with many branches coated in woolly white fibers and growing to a maximum height around a meter. The leaves are narrow, curving, and hooklike, hardening into sharp spines up to 2.5 centimeters long. The inflorescence
bears one or two flower heads
which are each enveloped in four to six woolly phyllaries
. Each head contains up to 8 tubular yellow flowers up to a centimeter long. The fruit is a densely hairy achene
which may be nearly 2 centimeters long, including its pappus
of long 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 shortspine horsebrush. It is native to the western United States, especially the basins and plateaus west of the Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
. It grows in sagebrush
Sagebrush
Sagebrush is a common name of a number of shrubby plant species in the genus Artemisia native to western North America;Or, the sagebrush steppe ecoregion, having one or more kinds of sagebrush, bunchgrasses and others;...
, woodlands, and scrub habitat, often among shadscale
Atriplex confertifolia
Atriplex confertifolia is a species of evergreen shrub in the Chenopodiaceae family, which is native to the western United States.-Habitat:Shadscale is a common, often dominant, shrub in the lowest and driest areas of the Great Basin...
in alkaline areas such as playas
Dry lake
Dry lakes are ephemeral lakebeds, or a remnant of an endorheic lake. Such flats consist of fine-grained sediments infused with alkali salts. Dry lakes are also referred to as alkali flats, sabkhas, playas or mud flats...
. It is a bushy shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
with many branches coated in woolly white fibers and growing to a maximum height around a meter. The leaves are narrow, curving, and hooklike, hardening into sharp spines up to 2.5 centimeters long. 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...
bears one or two flower heads
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
which are each enveloped in four to six woolly 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...
. Each head contains up to 8 tubular yellow flowers up to a centimeter long. The fruit is a densely hairy achene
Achene
An achene is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate and indehiscent...
which may be nearly 2 centimeters long, including its 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 bristles.