Onopordon acanthium is a plant species commonly known as the "cotton thistle." The spelling of this scientific name has roots in Latin and Greek, which combined create unique phonetic sounds that are represented through the International Phonetic Alphabet (IPA). The "o" in Onopordon is pronounced as "ah," while the second "o" is more of a schwa sound [ə]. The "c" in acanthium is pronounced as a hard "k," while the following "th" is a voiceless dental fricative [θ]. The final "ium" is pronounced as "ee-uhm."
Onopordon acanthium, commonly known as Scotch thistle or woolly thistle, is a herbaceous biennial plant that belongs to the Asteraceae family. It is native to Western Europe and is now distributed in temperate regions throughout the world.
The plant typically grows upright, reaching heights of up to 2 meters. It is characterized by its distinctive spiny leaves that are covered in a dense layer of white woolly hairs. The leaves, which can measure up to 30 centimeters in length, are deeply lobed and have a silvery appearance. During its second year of growth, Onopordon acanthium produces a substantial flowerhead that is typically pink or purple in color. The flowerhead consists of densely packed tubular florets that bloom atop a large receptacle.
Onopordon acanthium is known for its invasive tendencies, and it can rapidly colonize disturbed areas such as roadsides, pastures, and fields. It spreads primarily through its abundant seed production, which can be facilitated by wind dispersal or attachment to animals. Its spiny foliage makes it unpalatable to most herbivores, which further contributes to its ability to dominate areas of growth. Due to its aggressive nature, Onopordon acanthium is often considered a weed, and it can pose ecological and economic risks by outcompeting native plants and interfering with agricultural crops.
The word "Onopordon" is derived from the Greek words "onos" meaning "ass" and "pordē" meaning "thorn". This refers to the plant's characteristic thorny leaves. "Acanthium" comes from the Greek word "akantha", which means "thorn" as well, and is used to describe the spiny nature of the plant as a whole.