Arabis aculeolata
Encyclopedia
Arabis aculeolata is a species of flowering plant in the mustard family
known by the common name Waldo rockcress. It is native to a small range in the mountains of southern Oregon
and northern California
, where it is an uncommon member of the serpentine soil
s flora. This is a perennial herb growing from a tough caudex
covered in large hairs and the bases of leaves shed in previous seasons. It produces one or more erect stems to heights between 20 and 35 centimeters. The stems are dark in color, often reddish or purplish, and are coated in stiff white hairs. The leaves form a basal rosette about the caudex. They are oval-shaped, green in color and covered in white hairs, up to 4 centimeters long, and with smooth or wavy edges. Leaves located farther up the stem are smaller. The flowers have dark purple sepal
s and lighter purple petals. The fruit is a long, thin, erect silique
up to 6.5 centimeters long.
Brassicaceae
Brassicaceae, a medium sized and economically important family of flowering plants , are informally known as the mustards, mustard flowers, the crucifers or the cabbage family....
known by the common name Waldo rockcress. It is native to a small range in the mountains of southern 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 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 is an uncommon member of the serpentine soil
Serpentine soil
A serpentine soil is derived from ultramafic rocks, in particular serpentinite, a rock formed by the hydration and metamorphic transformation of ultramafic rock from the Earth's mantle....
s flora. This is a perennial herb growing from a tough 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...
covered in large hairs and the bases of leaves shed in previous seasons. It produces one or more erect stems to heights between 20 and 35 centimeters. The stems are dark in color, often reddish or purplish, and are coated in stiff white hairs. The leaves form a basal rosette about the caudex. They are oval-shaped, green in color and covered in white hairs, up to 4 centimeters long, and with smooth or wavy edges. Leaves located farther up the stem are smaller. The flowers have dark purple sepal
Sepal
A sepal is a part of the flower of angiosperms . Collectively the sepals form the calyx, which is the outermost whorl of parts that form a flower. Usually green, sepals have the typical function of protecting the petals when the flower is in bud...
s and lighter purple petals. The fruit is a long, thin, erect silique
Silique
A silique or siliqua is a fruit of 2 fused carpels with the length being more than three times the width. The outer walls of the ovary usually separate when ripe, leaving a persistent partition...
up to 6.5 centimeters long.