FINE-LEAVED WATER-DROPWORT

SULPHURWORT

Oenanthe aquatica

Carrot Family [Apiaceae]

month8jun month8june month8jul month8july month8aug month8sep month8sept

status
statusZnative
flower
flower8white
inner
inner8cream
morph
morph8hemizygo
petals
petalsZ5
type
typeZumbel
stem
stem8round
stem
stem8fluted
toxicity
toxicityZhigh
contact
contactZhigh

15th May 2018, Playden, Rye, Sussex Photo: © RWD
Has stout stems which are shiny and grows in either shallow(ish) still or slow-flowing freshwater.


15th May 2018, Playden, Rye, Sussex Photo: © RWD
The stems are often very substantial at water-level, getting thinner higher up, but hollow throughout. At each change in diameter of the main stem, a leafy branch peels off. These stems are telescopically set and very distinctive, but there are much thinner ones around (other aquatic plants such as a Water-Plantain on the left and another behind a Fine-leaved Water-dropwort also occupy this pond).


15th May 2018, Playden, Rye, Sussex Photo: © RWD
An isolared example. Each branch has an extended sheath (here coloured pale brown) around and part-way up the branches. When it is flowering (later in the year), a flowering branch emerges from the main stem but on the opposite side of each branch. [Another aquatic also occupies this pond: Water Violet - seen here flowering bottom right corner].


15th May 2018, Playden, Rye, Sussex Photo: © RWD
These two specimens are very sturdy near the waters' surface and taper upwards. It almost looks like a primordial plant standing in a swamp. The stems are hollow [another Water Violet stands with much a more delicate stem in front of it].]


15th May 2018, Playden, Rye, Sussex Photo: © RWD
The main stems are slightly ribbed but the branches are more noticeably grooved (presumably for stiffness) especially where they peel off the main stem. [Water Violet holds its stance amidst formidable opposition].


15th May 2018, Playden, Rye, Sussex Photo: © RWD
The striations and faintly ribbed or angular (depending which bit you look at) nature of the main stem and the deep grooves of the sheath around the branches [Water Violet dwarfed by the sturdiness of its neighbour].


15th May 2018, Playden, Rye, Sussex Photo: © RWD
It has 3 types of leaves. The upper leaves here are triply pinnate and opposite each other.


15th May 2018, Playden, Rye, Sussex Photo: © RWD
The leaflets of the upper leaves themselves are not pinnate, but have several lobes which are not cut to the centre-line (if they were the leaves would be 4-pinnate).


15th May 2018, Playden, Rye, Sussex Photo: © RWD
Upper leaves: The leaflets (pinna) have oval lobes in a 'pinnate' arrangement (but one which is not cut all the way to the centre-line and therefore not truely pinnate).


15th May 2018, Playden, Rye, Sussex Photo: © RWD
The lower leaves have filligree leaflets, which are still triply pinnate but the ultimate pinna are much more linear than oval. This specimen has a leaf which is abnormally paler than the rest - perhaps it is dying(?).


15th May 2018, Playden, Rye, Sussex Photo: © RWD
Lower leaves: The paler-green leaf. The pinna have a very different look and jizz to the upper leaves.


15th May 2018, Playden, Rye, Sussex Photo: © RWD
Lower leaves: filligree leaflets.


15th May 2018, Playden, Rye, Sussex Photo: © RWD
Lower leaves: filligree leaflets.


15th May 2018, Playden, Rye, Sussex Photo: © RWD
Lower leaves: filligree leaflets. They have a thinner look than those on the upper leaves.


15th May 2018, Playden, Rye, Sussex Photo: © RWD
Lower leaves: In close-up the pinna have almost but not quite linear lobes. Moreover the tips are pointed rather than the nearly blunt lobes of the Upper Leaves.


15th May 2018, Playden, Rye, Sussex Photo: © RWD
Lower leaves: The tips of the lobes have a short acuminate point.

[The third type of leaves Fine-leaved Water-dropwort has are underwater leaves (not shown) which have even finer (longer and truly linear) leaflets].

In reality, although this specimen has triply pinnate leaves, the plant can be 2-, 3-, or 4-pinnate.


Easily mistaken for : other Water-dropworts

Some similarities to : River Water-dropwort (Oenanthe fluviatilis) which grows in rivers (as can Fine-leaved Water-dropwort) but it doesn't seem to like still waters. But the fruits of River Water-dropwort are slightly larger at 5-6.5mm long (rather than the shorter 3-4.5mm of Fine-leaved Water-dropwort).

No relation to : Fine-leaved Goldilocks (Chrysocoma tenuifolia), Fine-leaved Sheep's-fescue (Festuca filiformis), Fine-leaved Fumitory (Fumaria parviflora) or Fine-leaved Vetch (Vicia tenuifolia) [plants with similar names belonging to differing families].

WATER-DROPWORTS:

Fine-leaved Water-dropwort, unlike all other Water-dropworts except River Water-dropwort, does not have tubers on the roots. Both are aquatic, the first occupying still water or slowly-flowing river water, the second either ascending or floating in slow-flowing rivers.

But the leaves of River Water-dropwort (and those of Tubular Water-Dropwort, Cork-fruited Water-dropwort, Parsley Water-Dropwort and Hemlock Water-Dropwort [sometimes 4-pinnate]) are only 1-3 pinnate (rather than the 2-4 pinnate of Fine-leaved Water-dropwort and the 1-4 pinnatre of Narrow-leaved Water-dropwort)

It also has hollow stems like all other Water-dropworts apart from Parsley Water-Dropwort and Cork-fruited Water-dropwort (which both have stems either solid with pith to 'hollow to some extent').

[Both Narrow-leaved Water-dropwort and Tubular Water-Dropwort have hollow stems but the walls of the stems are very thin]

All Water-dropworts either have (no bracts (Tubular Water-Dropwort) or usually no bracts) beneath the umbels apart from Cork-fruited Water-dropwort which has between 1 and 5 bracts beneath the umbels.


  Oenanthe aquatica  ⇐ Global Aspect ⇒ Apiaceae  

Distribution
 family8Carrot family8Apiaceae

 BSBI maps
genus8Oenanthe
Oenanthe
(Water-Dropworts)

FINE-LEAVED WATER-DROPWORT

SULPHURWORT

Oenanthe aquatica

Carrot Family [Apiaceae]