Digitalis obscura is a flowering plant, commonly known as the Sunset Foxglove or Willow-leaved Foxglove. It is native to regions in Spain and Africa, but can be grown as an ornamental flower around the world. It is a perennial woody plant belonging to the family Plantaginaceae. (Along with the other foxgloves it used to be placed in the figwort family, Scrophulariaceae; however, recent genetic research has moved the genus Digitalis to a larger family.) The Sunset Foxglove is similar to many of the foxglove species in its high toxicity and medicinal use as a source for the heart-regulating drug digitalis. Its strikingly distinctive amber- to copper-colored flowers give the species its name and help distinguish it from other members of the genus.
Description and habitat
Digitalis obscura is native to eastern to southern Spain and northern Africa. It occurs in both the mountains and the lowlands near the coast. However, it can be grown in many non-native areas as an ornamental plant. Digitalis obscura naturally grows well in dry climates and in high altitudes. Unlike many other foxgloves, it is drought-tolerant when it is deeply rooted and established. It thrives in average, well-drained soil with pH levels of 5.8–7.2. It may die if left in wet soil over winter. Digitalis obscura grows in either full or partial sun. It blooms during late spring from May to June and spreads over the ground about 0.75–1.5 feet. Once established, it is perennial and grows at a rather moderate to fast pace. It is non-invasive and attracts hummingbirds. It is naturally resistant to deer and rabbits.
Digitalis obscura is a shrub that grows about 1 to 2 feet (0.30 to 0.61 m) tall. The stems are smooth and erect. The long leaves are basal and form in a rosette fashion growing outward closer to the ground. Smaller leaves grow alternately along the stem. The thick, glossy leaves are lanceolate in shape, with acute tips. The leaves have a blue-green color and a leathery texture that gives them a shine.
The many flowers of the plant are large and tubular, opening into a funnel shape. They droop from the point of attachment to the stem, occurring in clusters on the same side of the floral axis. The flowers are approximately 1.5 inches (3.8 cm) long and have an appearance of dropping bells or snipped-off fingers as the common name of the genus, foxglove, suggests. The sunset foxglove is noted for its rusty dark-orange to green-yellow colored flowers that distinguishes it from the other foxgloves. Inside the flowers, red venation and spotting can also be seen as well as tiny hairs at the tips. The arrangement of the flowers in respect to the stalk is racemes and the flowers droop downward.
Digitalis obscura, like many of the other foxgloves, has been used in medicine as a diuretic and to treat heart conditions. For people suffering from heart disease or other heart-related conditions, it can be used to regulate heart rate. In human folk medicine, Digitalis obscura was used for many purposes, such as treating wounds and toothaches. However, the use of herbal medicinal remedies using Digitalis obscura has lessened to a great degree because of the knowledge of its high toxicity.
In ethnoveterinary medicine, the flowering stems of Digitalis obscura were traditionally used to promote wound healing and treat toothaches in animals. It is one of twenty-three species traditionally used in Granada to treat trauma or poisoning in animals.
All parts of Digitalis obscura are poisonous if ingested raw, including the roots and seeds. The most potent parts of the plant are the upper leaves.
All foxgloves are highly toxic if eaten because they contain various cardiac glycosides such as digitoxin, digitalin, digitonin, digitalosmin, gitoxin and gitalonin. During digestion, aglycones and a sugar are released by the breakdown of these glycosides. The aglycones directly affect heart muscles and may slow the heart rate until cardiac arrest occurs.
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- Benitez, Guillermo; M. Reyes González-Tejero, Joaquín Molero-Mesa (2011). "Knowledge of ethnoveterinary medicine in the Province of Granada, Andalusia, Spain". Journal of Ethnopharmacology 139 (2). Retrieved 4 April 2012.