Cynoglossum officinale[1] (houndstongue, houndstooth, dog's tongue, gypsy flower, and rats and mice due to its smell) is a herbaceous plant of the family Boraginaceae.
It can be either annual or biennial. Leaves are greyish and softly haired, lanceolate to oblong. Reddish-purple funnel-shaped flowers bloom between May and September.
The plant owes its common and scientific name to the long greyish leaves that are reminiscent of a dog's tongue and were once given as a remedy for dog bites.[2]
Found in most parts of Europe, and also North America, where it was accidentally introduced[3] including in British Columbia, where it is designated a noxious weed under the British Columbia Weed Control Act. It lives in wet places, sand dunes, waste land and hedges.
Houndstongue may be pollinated by bees, and may also self-pollinate.
The name "houndstongue" (and the Latin genus Cynoglossum) comes from the roughness of the leaf.
In 1725, houndstooth was presented in the family dictionary, Dictionaire oeconomique, as part of a cure for madness.[4] In that book, madness was viewed as "a distemper, not only of the understanding, but also of the reason and memory, proceeding from a cold, which drys up everything it meets with that is humid in the brain."[4] To cure madness, Dictionaire oeconomique noted:
In the 1830s, houndstooth was known in France to be made into an emollient and diuretic for daily use in inflammatory diseases, especially of the urinary organs.[5] To prepare as a diuretic, the houndstooth leaves were mashed, and then boiled in water to extract oils, volatile organic compounds, and other chemical substances.[5] The mix could be sweetened with liquorice to create Ptisan of Dog's-grass.[5] After decoction, the herbal tea was taken internally a cupful at a time.[5] In 1834, the Hospital of Paris provided a formula of 2/3 ss—J to Oij of water for houndstooth tea.[5] By the end of the 1830s, doctors in England were using houndstooth as an antiaphrodisiac to combat venereal excesses.[6]
Herbalists use the plant for piles, lung diseases, persistent coughs, baldness, sores, and ulcers but the effectiveness of all these uses is not supported by any scientific evidence.[7]
In 1891, the U.S. state of Michigan identified houndstooth, along with flea-bane, rag weed, burdock, cockle-bur, and stickseed, as some of the worst weeds in the state.[8]
Cynoglossum officinale contains tumorigenic pyrrolizidine alkaloids.[9] It is toxic to cows and is especially dangerous to pasture owners.[3]
. Blanchan, Neltje. Wild Flowers: An Aid to Knowledge of our Wild Flowers and their Insect Visitors. 2002. Project Gutenberg Literary Archive Foundation. Neltje Blanchan. Wild Flowers: An Aid to Knowledge of our Wild Flowers and their Insect Visitors.