WATER SOLDIER

Stratiotes aloides

Frogbit Family [Hydrocharitaceae]  

month8jun month8june month8jul month8july month8Aug

status
statusZnative
flower
flower8white
inner
inner8yellow
morph
morph8actino
petals
petalsZ3
stem
stem8round
rarity
rarityZuncommon
sex
sexZdioecious

27th June 2009, Mcr Bolton & Bury canal, Elton. Photo: © RWD
An army of Water Soldiers. Given half a chance (and no boats) it spreads uncontrollably.


3rd Aug 2007, Hollingworth Canal, Daisy nook, Gtr Manchester. Photo: © RWD
Unimpeded by roots in the ground in Summer it rises by means of gas-filled leaves from the shallow depths to the surface in order to flower.


30th Aug 2009, Mcr Bolton & Bury canal, Elton. Photo: © RWD
More or less the same section of canal, but two months later and the Water Soldiers are retreating (sinking) in the face of an advancing army - a floating carpet of reddish-brown Water Fern. The Water Fern is also interspersed with Parrot's Feather: three weeds each vying for dominance have solved the problem by time-sharing. [The narrow clear channel is made by water birds rather than by boats].


27th June 2009, Mcr Bolton & Bury canal, Elton. Photo: © RWD
A reluctant flowerer. If any one plant flowers at all, then it usually has but one flower.


27th June 2009, Mcr Bolton & Bury canal, Elton. Photo: © RWD
 A single white three-petalled flower amidst a sward of swords.


27th June 2009, Mcr Bolton & Bury canal, Elton. Photo: © RWD
 Each plant has sword-like leaves that splay out like an upturned half-opened umbrella without the cloth.


27th June 2009, Mcr Bolton & Bury canal, Elton. Photo: © RWD
 The three white leaves and central yellow area. All UK specimens are female, with 6 white, forked styles. they reproduce entirely vegetatively here.


27th June 2009, Mcr Bolton & Bury canal, Elton. Photo: © RWD
 It seems to effuse a smell attractive to small flies.


27th June 2009, Mcr Bolton & Bury canal, Elton. Photo: © RWD
 All flowers of Water Soldier in the UK are female, apart from a select few male-only plants in Southern England.


3rd Aug 2007, Hollingworth Canal, Daisy nook, Gtr Manchester. Photo: © RWD
It retires during late autumn, gradually losing the bouyant gas from its leaves, slowly sinking again.


27th June 2009, Mcr Bolton & Bury canal, Elton. Photo: © RWD
The sword-like leaves have sharp serrations similar to the teeth on a hacksaw blade. With their saw-teeth and splayed appearance the leaves resemble those of the plant Aloe, hence the scientific name Stratiotes aloides.


25th May 2013, Mcr Bolton & Bury canal, Nob End, Ringley. Photo: © RWD
Over winter the leaves stop photosynthesizing, and without the constant production of photosynthetic gas (oxygen, but that will gradually diffuse out) which inflates the interstitial spaces between cells in the leaves they sink to the bottom of the water. When fully submerged the leaves turn a browny-green. On the bottom where the still waters are unlikely to freeze even in the coldest of winters, it is protected from the harsh low temperatures likely to be experienced above water.


25th May 2013, Mcr Bolton & Bury canal, Nob End, Ringley. Photo: © RWD
Despite appearances, and through wiley photography, these plants are fully submerged below the water. As spring approaches and the sun shines bright enough to reach deeper waters the leaves start photosynthesizing again, producing oxygen which inflates the leaves enough to give the plant bouyancy, and it starts to rise to the surface again.


25th May 2013, Mcr Bolton & Bury canal, Nob End, Ringley. Photo: © RWD
Still fully submerged but slowly rising from the depths again. The reddish leaves are new growth, the colour affording new leaves some protection from sunburn. Only the fine hairs of the long roots bury themselves in the sediment. Leaf rosettes grow at intervals along the submerged runners; it spreads vegetatively.


Uniquely identifiable characteristics

Distinguishing Feature : the half-submerged up-turned-palm look of the sword-shaped serrated leaves.

No relation to : Gallant Soldier [a plant with similar name]

The sword-shaped leaves are very brittle and easily snapped in two, which is the main method of reproduction: vegetative reproduction, although sexual reproduction does occur too. [In the authors opinion, however, a fleet of narrowboats proceeding down a cut infested with Water Soldier, will, in a season, soon destroy the colony rather than spread it further. How many navigable canals are infested with Water Soldier?]. It is dioecious, with male and female flowers on separate plants. However, in the UK, almost all plants are female, although there some hermaphroditic plants in Southern Britain. Very few, if any, are all male.

It grows best in iron-containing peaty-sediments that are reducing (rather than oxidising) and will gradually die if the sediment is too rich in iron. It was once used for treating wounds, especially any made by an iron implement, for it uses up the iron. Too much iron in the water results in sulfide poisoning, and this may account for the decline in Water Soldier in the UK in recent decades. It could be significant that mostly wooden narrow-boats plied this section of the canal, which was near closure when steel-hulled boats arrived.

It's status in the UK is open to question, being either Native or Alien. It is sold as an attractive water plant for gardens and has been thrown out into other watery places, usually an un-used canal is where it often takes up residence, for it likes still water and little interference from boats.


  Stratiotes aloides  ⇐ Global Aspect ⇒ Hydrocharitaceae  

Distribution
family8Frogbit family8Hydrocharitaceae

 BSBI maps
genus8Stratiotes
Stratiotes
(Water-soldier)

WATER SOLDIER

Stratiotes aloides

Frogbit Family [Hydrocharitaceae]  

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