''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
The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...
. It grows in
sagebrush
Sagebrush is the common name of several woody and herbaceous species of plants in the genus ''Artemisia''. The best known sagebrush is the shrub ''Artemisia tridentata''. Sagebrushes are native to the North American west.
Following is an alph ...
, woodlands, and scrub habitat, often among
shadscale
''Atriplex confertifolia'', the shadscale or spiny saltbush, is a species of evergreen shrub in the family Amaranthaceae, which is native to the western United States and northern Mexico.
Description
The height of ''Atriplex confertifolia'' vari ...
in alkaline areas such as
playas. It is a bushy
shrub
A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...
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
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. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...
bears one or two
flower heads
A pseudanthium (Greek for "false flower"; ) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, compos ...
which are each enveloped in four to six woolly
phyllaries
In botanical terminology, a phyllary, also known an involucral bract or tegule, is a single bract of the involucre of a composite flower. The involucre is the grouping of bracts together. Phyllaries are reduced leaf-like structures that form one or ...
. Each head contains up to 8 tubular yellow
disc flowers
The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...
up to 1 cm long. The fruit is a densely hairy
achene
An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...
which may be nearly 2 cm long, including its
pappus of long bristles.
The plant is extremely toxic, although it is unpalatable and unlikely to be eaten. Consumption causes
liver damage
Liver disease, or hepatic disease, is any of many diseases of the liver. If long-lasting it is termed chronic liver disease. Although the diseases differ in detail, liver diseases often have features in common.
Signs and symptoms
Some of the sig ...
and extreme
light sensitivity Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light. In medicine, the term is principally used for abnormal reactions of the skin, and two types are distinguished, photoallergy and phototoxicity ...
, which in combination may be deadly.
The latter effect is caused by a pigment entering the superficial
circulatory system
The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, tha ...
, producing a
sunburn
Sunburn is a form of radiation burn that affects living tissue, such as skin, that results from an overexposure to ultraviolet (UV) radiation, usually from the Sun. Common symptoms in humans and animals include: red or reddish skin that is ho ...
-like effect as well as swelling around the head in light-colored animals, particularly sheep.
References
External links
Jepson Manual TreatmentFlora of North AmericaPhoto gallery
Senecioneae
{{Senecioneae-stub