FIELD HORSETAIL

Equisetum arvense

Horsetail Family [Equisetaceae]

month8apr month8april month8may month8jun month8june month8jul month8july month8aug month8sep month8sept month8oct

Spores:
month8apr month8april

status
statusZnative
 
petals
petalsZ0
(0)
stem
stem8round
 
stem
stem8ribbed
(6-20)
stem
stem8hollow
 
toxicity
toxicityZmedium
 

APRIL - EARLY IN THE SEASON

19th April 2016, grassy sands, Hall Road, Sefton Coast. Photo: © RWD
The leafless fertile growths appear usually before the sterile photosynthetic stems.


19th April 2016, grassy sands, Hall Road, Sefton Coast. Photo: © RWD
The fertile stems are white or pinkish with fawn and grow to 30cm or so. They lack chlorophyll and cannot photosynthesize. As does the similar and common Great Horsetail, and the less common Shade Horsetail and Wood Horsetail.


19th April 2016, grassy sands, Hall Road, Sefton Coast. Photo: © RWD
The sheath around each slightly swollen node has spreading and long teeth.


19th April 2016, grassy sands, Hall Road, Sefton Coast. Photo: © RWD
The fertile tips are encircled by numerous rings of haxagonal brown discs, angled outwards, with numerous off-white spore sacs peeping out like teeth.


19th April 2016, grassy sands, Hall Road, Sefton Coast. Photo: © RWD
The white spore sacs are sometimes known as 'teeth' for a good reason.


19th April 2016, grassy sands, Hall Road, Sefton Coast. Photo: © RWD
The arrangement of the spore-sacs, hanging downwards, differs from the otherwise very similar Great Horsetail where they instead are directed inwards, and less obviously seen.


19th April 2016, grassy sands, Hall Road, Sefton Coast. Photo: © RWD
The numerous spore-sacs are attached to hexagonal brown plates.


19th April 2016, grassy sands, Hall Road, Sefton Coast. Photo: © RWD
Hexagonal plates.


19th April 2016, grassy sands, Hall Road, Sefton Coast. Photo: © RWD
Mis-shapen creamy-white sacs containing the spores. They fall off when ripe.


19th April 2016, grassy sands, Hall Road, Sefton Coast. Photo: © RWD
Brown hexagonal plate with raised edging.


MAY - A LITTLE LATER IN THE SEASON

17th May 2009, on banks of a brook, The Burrs, Bury, Lancs. Photo: © RWD
The whorls of leaves (branches) up the stem have not yet fully grown in length.


17th May 2009, on banks of a brook, The Burrs, Bury, Lancs. Photo: © RWD
Both stems and branches have teeth around each node. The nodes will readily detach if pulled.


17th May 2009, on banks of a brook, The Burrs, Bury, Lancs. Photo: © RWD
The leaves (branches) have spreading and acutely-tapered teeth at each node. Branches 1-2mm in diameter are wavy and solid (not hollow).


17th May 2009, on banks of a brook, The Burrs, Bury, Lancs. Photo: © RWD
The stems have long teeth, as many as there are ridges (6-18).


17th May 2009, on banks of a brook, The Burrs, Bury, Lancs. Photo: © RWD


JULY - EVEN LATER IN THE SEASON

5th July 2014, by a ditch, Rimrose Valley Country Pk, Waterloo, Sefton Coast. Photo: © RWD


5th July 2014, by a ditch, Rimrose Valley Country Pk, Waterloo, Sefton Coast. Photo: © RWD
Mature branches can be quite long and devious.


5th July 2014, by a ditch, Rimrose Valley Country Pk, Waterloo, Sefton Coast. Photo: © RWD
Stems 2.5 - 4mm diameter, sometimes slightly rough with usually 9-13 shallow rounded ridges, but up to 6-18. The inner 1/3 of the stem is hollow as well as a ring of smaller hollow areas surrounding the central area. Stems without a tough stele (i.e. are easily pulled apart or broken).


5th July 2014, by a ditch, Rimrose Valley Country Pk, Waterloo, Sefton Coast. Photo: © RWD
The branches are 4-angled (as are those of Wood Horsetail and sometimes Wilmot's Horsetail and Dyce's Horsetail. Sheath teeth are 2-ribbed


Not to be semantically confused with : Horseradish (Armoracia rusticana) nor with Horse-Chestnut (Aesculus hippocastanum) [plants with similar names belonging to a differing families]

Hybridises with :

  • Great Horsetail (Equisetum telmateia) to produce Anglesea Horsetail which only occurs in one hectad of Anglesea.
  • Marsh Horsetail (Equisetum ) to produce (Equisetum × rothmaleri) which is found in North Hertfordshire and in Scotland.
  • Water Horsetail (Equisetum fluviatile) to produce Shore Horsetail (Equisetum × litorale) which is found throughout the British Isles in wettish places such as by rivers and lakes, in ditches and dune-slacks.

Many similarities to : Great Horsetail (Equisetum telmateia) which, along with the less common Shade Horsetail (Equisetum pratense) and Wood Horsetail (Equisetum sylvaticum), have a whitish fertile stem which lacks chlorophyll followed by a photosynthetic stem which is green with branches.

Uniquely identifiable characteristics

Distinguishing Feature : see text and captions.

Grows in grassland and damp grassy places, dune-slacks, rough, waste and cultivated ground and gardens where it is a persistent weed hard to eliminate. It is abundant throughout the UK and is much the more frequent horsetail in the drier grassy and waste places.

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

The main stems, on the other hand, usually have more ridges: On Field Horsetail they number between 6-20 and are rounded ridges (rather than the 18-60 (up to 60) shallow grooves of the similar Great Horsetail (Equisetum telmateia).


  Equisetum arvense  ⇐ Global Aspect ⇒ Equisetaceae  

Distribution
 family8Horsetail family8Equisetaceae

 BSBI maps
genus8Equisetum
Equisetum
(Horsetails)

FIELD HORSETAIL

Equisetum arvense

Horsetail Family [Equisetaceae]