Thistle

Thistle is the common name of a group of flowering plants characterized by leaves with sharp prickles on the margins, mostly in the family Asteraceae. Prickles often occur all over the plant – on surfaces such as those of the stem and flat parts of leaves. These are an adaptation that protects the plant against herbivorous animals, discouraging them from feeding on the plant. Typically, an involucre with a clasping shape of a cup or urn subtends each of a thistle's flowerheads.

The term thistle is sometimes taken to mean exactly those plants in the tribe Cynareae (synonym: Cardueae), especially the genera Carduus, Cirsium, and Onopordum. However, plants outside this tribe are sometimes called thistles, and if this is done thistles would form a polyphyletic group.

Thistle is the floral emblem of Scotland, as well as the emblem of the Encyclopaedia Britannica.

Taxonomy

Genera in the Asteraceae with the word thistle often used in their common names include:

Thistle (disambiguation)

Thistle is a group of flowering plants.

Thistle may also refer to:

Football (soccer) clubs

Australia

England

New Zealand

Scotland

Boats and ships

Shades of purple

There are numerous variations of the color purple, a sampling of which are shown below.

In common English usage, purple is a range of hues of color occurring between red and blue.

In color theory, purple colors are any colors on the line of purples on the CIE chromaticity diagram (or colors that can be derived from colors on the line of purples), i.e., any color between red and violet, not including either red or violet themselves.

The first recorded use of purple as a color name in English was in 975.

Historical development of purple

Tyrian purple: Classical antiquity

See also under Purple#In art and history the section "In prehistory and the ancient world: Tyrian purple"

The actual color of Tyrian purple, the original color purple from which the name purple is derived, is the color of a dye extracted from a mollusk found on the shores of the city of Tyre in ancient Phoenicia (present day Lebanon) that in classical antiquity became a symbol of royalty because only the very wealthy could afford it. Therefore, Tyrian purple was also called imperial purple.