About Achillea erba-rotta All.
Achillea erba-rotta All. is a polymorphic species, meaning its physical characteristics vary noticeably depending on the variety. It has a chamaephyte suffruticose biological form: its perennating buds grow close to the ground, the lower part of its stem is woody, and it produces annual herbaceous branches. Its primary root structure is a rhizome. Mature plants reach an average height of 12 to 18 centimetres (4 3/4 to 7 inches). The plant's stems are woody and creeping, nearly hairless or covered in short hairs, and bear erect flowering branches. Leaves on sterile branches are lanceolate-spatulate, measuring 5 to 7 millimetres (3/16 to 1/4 inch) wide and 26 to 30 millimetres (1 to 1 1/8 inch) long, with 4 to 7 teeth along each edge. Cauline (stem) leaves are alternate, sessile, toothed, and become progressively more linear toward the top of the stem; they measure around 2 to 3 millimetres (1/16 to 1/8 inch) wide and 11 to 22 millimetres (7/16 to 7/8 inch) long. Flowers bloom from July to August; they are hermaphroditic, pentamerous, and arranged in many-headed corymbs. Each flower head is about 3 millimetres in diameter and has rounded ligules. The fruit produced is a flattened achene with no pappus. This species is a characteristic alpine plant, found in Italy, France, Switzerland, and Austria. It grows best in sunny locations in alpine pastures and rocky areas, at altitudes between 2,000 and 2,800 metres (6,600 to 9,200 feet) above sea level.
