GREAT HORSETAIL

Equisetum telmateia

Horsetail Family [Equisetaceae]  

Stems:
month8apr month8april month8May month8jun month8june month8jul month8july month8Aug month8sep month8sept month8Oct month8Nov

Spores:
month8apr month8april

status
statusZnative
 
petals
petalsZ0
(0)
stem
stem8round
 
stem
stem8ribbed
18-40
stem
stem8hollow
 
toxicity
toxicityZmedium
 

3rd May 2013, Consal Forge, Caldon Canal, Staffs. Photo: © RWD
Forms large patches near water or in damp ground, especially on clay.


3rd May 2013, Consal Forge, Caldon Canal, Staffs. Photo: © RWD
Grows in damp places often near water, but never in water; that would be Water Horsetail (or a similar plant, Marestail).


3rd May 2013, Consal Forge, Caldon Canal, Staffs. Photo: © RWD
At first the fertile spike arises from the ground.


3rd May 2013, Consal Forge, Caldon Canal, Staffs. Photo: © RWD
The light-green stem of the fertile spike has regularly-spaced sections with brown/black whorls, the toothed sheaths.


2nd April 2014, Yarrow Valley Country Park, Chorley, Lancs. Photo: © RWD
As it grows the individual sporing bodies become separated.


3rd May 2013, Consal Forge, Caldon Canal, Staffs. Photo: © RWD
The tip of the stem has an extended pale-green progressing through pale-fawn to brown tip, a colour and shape unlike any other Horsetail. This is a cone and is covered in small flat-topped short projections not un-like those on some table-tennis bats which bear the spores. The projections start off at the bottom in ordered rings but quickly degenerates into a random arrangement.


2nd April 2014, Yarrow Valley Country Park, Chorley, Lancs. Photo: © RWD
Each individual sporing 'floret' is quite long, and is supported by several green cylindrical structures, the spore-sacs. The assembly has a totally differing appearance to that of the very similar Field Horsetail.


2nd April 2014, Yarrow Valley Country Park, Chorley, Lancs. Photo: © RWD
The green structures merge at the top into a single sporing body. Presumably ripe ones are brown? Note the efficient mostly hexagonal packing.


2nd April 2014, Yarrow Valley Country Park, Chorley, Lancs. Photo: © RWD
And immature ones are white?


3rd May 2013, Consal Forge, Caldon Canal, Staffs. Photo: © RWD
The toothed sheaths overlap at first but become separated as the fertile spike grows taller.


15th June 2004, Rowsleymoor wood, Rowsley, Derbyshire. Photo: © RWD
Only after the fertile spikes have spored do the branched infertile stems grow. They are like green bottle-brushes, up to 2m in height.


2 Aug 2005, Parbold, Leeds & Liverpool Canal. Photo: © RWD
The stem is again in sections and is light-green.


2 Aug 2005, Parbold, Leeds & Liverpool Canal. Photo: © RWD
Each section has a toothed sheath, but un-like the fertile stalk also has a whorl of wire-like green leaves.


2 Aug 2005, Parbold, Leeds & Liverpool Canal. Photo: © RWD
The leaves are in a whorl just below each light-green sheath, with the teeth just above the light-green sheath.


Some similarities to : Marestail (Hippuris vulgaris), which grows in shallow water, has whorls of wiry leaves which are shorter than those of Horsetails and which belongs to a differing family (Hippuridaceae).

Hybridises with:

  • Field Horsetail (Equisetum arvense) to produce Anglesey Horsetail which only occurs in one hectad of Anglesea.
  • Water Horsetail (Equisetum fluviatile) to produce Equisetum × willmotii which occurs in but a handful of hectads in the UK.
  • Marsh Horsetail(Equisetum palustre) to produce Equisetum × font-queri which occurs mainly in Lancashire.
  • Wood Horsetaill(Equisetum sylvaticum) to produce Equisetum × bowmanii which occurs in only 3 hectads in the UK.
The fertile stems shown in the above photos, taken in Staffordshire, are un-likely to be hybrids, since none occur in the area. However, the infertile photos from Parbold do occur in a region where the hybrid with Marsh Horsetail is extant, but it is not known whether or not those photos are of any hybrids.

Uniquely identifiable characteristics

No relation to : Horseradish, Horse-Chestnut [plants with similar names belonging to differing families]

The fertile spikes are without leaves and appear before the infertile spikes bearing whorls of wire-like green leaves. Both stalks and leaves are in sections which, if pulled hard, will part company. Great Horsetail is the tallest Horsetail, and easily recognised by the fawn-coloured long tip of the fertile spike bearing the spores. It is by far the tallest Horsetail, the sterile light-green stems with whorls of wire-like leaves growing to 2m. It grows near water or in damp ground but never in the water as does Water Horsetail (Equisetum fluviatile).

The branches of the photosynthetic stems are 8-angled [as opposed to 3-angled for Shady Horsetail (Equisetum pratense); 4-angled for Wood Horsetail (Equisetum sylvaticum) and for Field Horsetail (Equisetum arvense); 5-angled for Variegated Horsetail (Equisetum variegatum); and 6- to 7- (up to 10)-angled for Branched Horsetail (Equisetum ramosissimum)]

The main stems, on the other hand, usually have more ridges: On Great Horsetail they number between 18-40 (up to 60) and are faint grooves.

The horsetails are very primitive non-flowering spore-bearing plants. Like Ferns, such as Bracken, Horsetails also contain Thiaminases which eliminate Vitamin B1 (Thiamine) from the body, causing disease.

A TOXIC POLYCYCLIC PEPTIDE ALKALOID

Horsetails are poisonous and many contain much the same toxins, such as Palustrine, but in differing proportions. Great Horsetail is more toxic than most, having higher concentrations of the toxins.

Palustrine (aka palustrin) is a polycyclic peptide that can gum up the workings of the normal mammalian body if ingested, such as by sheep, oxen or cows but especially by horses, when the intoxication is then called equisetosis. The characteristic symptoms are breathing disorders, digestive problems and possibly fever. The alkaloids exhibit oxytocic properties, where females can lose their off-spring, which can also happen to pregnant women who consume Horsetail plants. Marsh Horsetail (Equisetum palustre) has an especially high concentration of Palustrine, hence the name of the alkaloid. Marsh Horsetail (and possibly other horsetails too) also has derivatives of Palustrine, such as N-FormylPalustrine, N-AcetylPalustrine, Palustridine [N.B. Not Palustridiene, as some sources spell it!] (with the H on the right-most N-atom replaced by CHO) and N-FormylPalustridine. All contain a lactam ring. On alkali fusion Palustrine yiends Spermidine.

[There is another molecule with the same common name as Palustrine which is not related in any way to the above]


  Equisetum telmateia  ⇐ Global Aspect ⇒ Equisetaceae  

Distribution
family8Horsetail family8Equisetaceae

 BSBI maps
genus8Equisetum
Equisetum
(Horsetails)

GREAT HORSETAIL

Equisetum telmateia

Horsetail Family [Equisetaceae]  

WildFlowerFinder Homepage