Uniquely identifiable characteristics : there is no other plant with the same appearance (as long as the flowers are visible).
Distinguishing Feature : The distinctive flowers.
Easily confused with : Butterbur when the flowers have gone and only the leaves are visible.
The flower stems are hollow and quite thick for the size of the plant, are covered in white felty hairs, and have very short stubby over-lapping scales, which can turn quite red after strong prolonged sunshine. The flowers have a distinct tendency to droop bending over double like umbrella handles before fully opening and standing upright. It is a very early flowerer, starting in January well before most
Dandelions and continuing through March when Dandelions start appearing through to April.
The leaves are generally absent during flowering, appearing only before flowering then withering away before the flowers have bloomed. Frequently a white cobweb of hairs covers the leaves, but that soon disappears to reveal matt-green leaves with distinctive thin white veins, reddish beneath the leaf. The leaves are cardioid in overall shape with dentate edges - having several large-radius concave edges. Leaf stems appear to be square and reddish.
The flowers have both ray and disc florets. The ray florets being very numerous but wire-thin. The disc florets are a deeper shade of yellow bordering on orange. Between them is a haze of thin yellow stamens.
The seed head is, unlike a dandelion clock, at first flattened on top like a mushroom, with a distinctive inner brown circle; the seeds themselves, which unlike those of Dandelion, are long and cylindrical as well as more brown. The seed-clock may get weather-beaten into other untidy shapes more like windswept dandelion clocks. They were used as a stuffing for pillows.
An extract can be prepared from the roots of Colt's-foot. It is used as an expectorant for cough relief, and in the confectionery known as Colt's-foot Rock, which is in the shape of a Doric-fluted fawn-coloured stick about a centimetre in diameter and 10 centimetres long. It is sweet (with added sugar) and can be sucked like a stick of rock. Colt's-foot Rock, made to a traditional recipe, contains Parogoric (a camphorated tincture of opium), capsicum, oil of aniseed and colt's-foot extract at 0.0012% concentration as the active ingredients. Both a wine (Clayt) and a beer (Cleats) can be made with Colt's-foot root.
Despite belonging to the extensive Daisy Family, which usually contain highish levels of toxic pyrrolizidine alkaloids (PA's), Colt's-foot has a low PA content.
The name Colt's-foot refers to the shape of the leaf, which is in the shape of the footprint of a colt. The scientific name Tussilago is derived from the Latin Tussis meaning 'cough'; it is used in cough mixtures.
Both Senecionine and Senkirkine are poisonous Pyrrolizidine Alkaloids found in Colt's-foot. Senecionine is also found in a number of other plants such as
Ragwort but is only a minor constituent in Colt's-foot. Both are hepatotoxic and can poison the liver if consumed and can act as indirect mutagens. Both are present in the leaves and flower stalks. Senkirkine is more mutagenic than Senecionine and most other Pyrrolizidine Alkaloids and occurs in Colt's-foot at greater concentrations. Senecionine is shown for comparison; it is better detailed elsewhere (see Tansy and Oxford Ragwort.
The Cinnabar moth, which in the caterpillar stage normally feeds on Ragwort to obtain its poisonous pyrrolizidine alkaloids, will switch to Colt's-foot as an alternative source. The Cinnabar moth uses the poisons as a predator deterrent.
Other compounds present are the sesquiterpenoid glycoside
isopetasoside and its aglycone (without the attached sugar molecule) the phytotoxin sesquiterpenoid isopetasol. Petasol and Isopetasol are potentially of use as herbicides. The only difference between Petasol and Isopetasol is the position of the double bond on the side chain. Petasol and Isopetasol also occur in Butterbur (Petasites hybridus) from which it derives its name.
Compare the above with the sesquiterpenoides Petasin and IsoPetasin which occur in Butterbur.