TUBULAR WATER-DROPWORT

Oenanthe fistulosa

Carrot Family [Apiaceae]

month8jun month8june month8jul month8july month8aug month8sep month8sept

status
statusZnative
 
flower
flower8white
 
inner
inner8pink
 
morph
morph8hemizygo
 
petals
petalsZ5
 
type
typeZumbel
 
stem
stem8round
 
stem
stem8ribbed
slightly
stem
stem8hollow
 
toxicity
toxicityZhigh
 
contact
contactZhigh
 
sex
sexZbisexual
 
sex
sexZmale
 

23rd July 2016, Ainsdale Dunes, Sefton Coast. Photo: © RWD
Most of the taller plants with white flowers atop are Tubular Water-dropwort whilst the shorter foreground off-white flowers are those of Fool's-Water-cress. (There are also a few other plants scattered in the wet area).


23rd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
Those with paler-green with tall, branched stems (some of which are slightly swollen in the middle) and with white flowers atop are Tubular Water-dropwort. (There are other plants also in this wet area). Grows up to 80cm tall.


21st July 2018, Ainsdale Dunes, Sefton Coast. Photo: © RWD
An isolated Tubular Water-dropwort showing the zig-zag nature of the branches. The whole plant is without hairs.


21st July 2018, Ainsdale Dunes, Sefton Coast. Photo: © RWD
At the risk of absorbing toxic polyynes through his skin your Author gingerly uprooted this specimen and held it aloft so that the features can be better seen. The whole stem is a glaucous green, unlike the brighter green of the similar Parsley Water-Dropwort with which it likes to grow amongst. At every branch there is a slightly constricted node. The stems are slightly thicker in the middle of each section, a characteristic feature of Tubular Water-dropwort. The lower branched nodes have sheathed 'branches' which are not tubular (although they may give that impression - but they are split at the top - thus rolled leaves) - they also taper towards the end where some short narrow leaflets stick out. Your Author can find 12 such leaflet groups on this specimen.

Note the two globed fruits near the summit.



21st July 2018, Ainsdale Dunes, Sefton Coast. Photo: © RWD
The lower 2 branches have brown withered and sheathed leaves under each branch. The other leaves visible are all 1-pinnate with linear leaflets (they can be 2- or rarely 3-pinnate) with either linear (or lanceolate) leaflets.


21st July 2018, Ainsdale Dunes, Sefton Coast. Photo: © RWD
The branched stems are hollow with faint ridges/grooves, branched nodes pinched narrow and may bulge gradually but only slightly near the centre between nodes. Leaves begin sheathed around the stems at branched nodes.


21st July 2018, Ainsdale Dunes, Sefton Coast. Photo: © RWD
A branched node with a sheathed leaf under the branch. Ridges/grooves very slight.


2nd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
A pinnate leaf with linear leaflets.


2nd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
A pinnate leaf with linear leaflets which are hooked at the tips just like the styles on the fruit are (and here reddened there too).


2nd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
Translucent sheath at stem junction at bottom of photo. Flowers on the terminal umbel (at the top of the plant) have both hermaphrodite (aka bisexual) flowers as well as some male flowers - whereas any lateral umbels (those on branches at the side of the main inflorescence) are male flowers.


2nd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
The stem emerges from the grimpen mire. Note the broken stem on the right showing how hollow they really all are.


23rd July 2015, Birkdale Dunes, Sefton Coast. Photo: © RWD
The constrictions on the very hollow stems are there to possibly(?) help keep water up inside the hollow stem by means of some sort of restriction inside at the junctions?.


2nd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
This specimen with a main umbel of four. And the reddish hooked tips to the linear leaves at the top (on the left).


2nd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
The 4-way umbel is asymmetric. Flowers fresh.


2nd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
The reddish hooked tips to the linear leaves. Are they to help it spread??


2nd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
This specimen has an umbel of 4 umbellets. There are no bracts beneath the major umbel, only beneath the umbellets. On the left is a pinnate leaf bearing several linear leaflets.


21st July 2018, Ainsdale Dunes, Sefton Coast. Photo: © RWD
Here with umbels of pinkish-white flowers on pinkish stalks. It seems that the anthers are initially lime-green.


21st July 2018, Ainsdale Dunes, Sefton Coast. Photo: © RWD
The umbels lack bracts, but the umbellets above them have a ring of short linear bracts beneath them (here pinkish and curving upwards). The terminal umbels have mainly hermaphrodite flowers with some male flowers (the lateral umbels with male only flowers).


21st July 2018, Ainsdale Dunes, Sefton Coast. Photo: © RWD
Densely packed flowers in centre (possibly hermaphroditic) with larger (possibly male-only) flowers on the periphery. Anthers now brownish.


2nd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD


2nd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
Smaller inner flowers (possibly hermaphroditic).


2nd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
The bracteoles beneath an umbellet number between 7 to 16.


2nd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
The sepals cupping each flower are 5 in number, with longer sepals on the outerside of the outer flowers. The rays, just like the hollow stems of the main plant, are striated or faintly ribbed.


2nd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
A larger male-only(?) flower on the outside of the bunch.


21st July 2018, Ainsdale Dunes, Sefton Coast. Photo: © RWD
An older specimens here and below:
Only a single main branch harbours the flowering head, which may radially divide into 3 (as here) or anything between 2 and 6 times, with each branch growing an umbellet of white or pinkish-white flowers.


21st July 2018, Ainsdale Dunes, Sefton Coast. Photo: © RWD
It seems to be more usual for the umbel to divide into 3 umbellets via rays which are between 1 to 3cm long, which thicken after flowering.


23rd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
Two denser inflorescences and a sparse one.


23rd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
A less dense umbellet showing the highly zygomorphic nature of the outer flowers compared to the inner ones


23rd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
A domed umbellet with large outer florets.


23rd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
The outer florets are highly zygomorphic, with an extra-long outer petal. All 5 petals are sometimes folded backwards and have a notched tip.


23rd July 2015, Ainsdale Dunes, Sefton Coast. Photo: © RWD
The anthers are very long and straggly, projecting well proud of the petals.


21st July 2018, Ainsdale Dunes, Sefton Coast. Photo: © RWD
The globed fruits, here in an umbel of two. Upper leaflets have very few linear leaflets in a pinnule.


21st July 2018, Ainsdale Dunes, Sefton Coast. Photo: © RWD
The aglomeration of fruits is almost globular in shape and looks strangely similar to the burrs on Lesser Burdock (and other Burdocks) or on Pirri-pirri-bur with their long burred styles sticking out.


21st July 2018, Ainsdale Dunes, Sefton Coast. Photo: © RWD
The individual fruits are widest nearer the top, each 3 to 4mm long and with styles at least as long as the fruit topped by a stigma which is slightly hooked at the end. (The brownish untidy parts are the remains of the petals).


21st July 2018, Ainsdale Dunes, Sefton Coast. Photo: © RWD
The hooked styles, possibly designed to carry the fruits on fur some distance from the plants present location.


21st July 2018, Ainsdale Dunes, Sefton Coast. Photo: © RWD
This umbel unusually has five! rays. Either all the fruits have dropped off leaving just the 5 sepals, or this umbel had all male flowers (therefore fruits cannot develop).


21st July 2018, Ainsdale Dunes, Sefton Coast. Photo: © RWD
The lowest branch with withered sheathed leaf beneath. The muddy section of the stem was below water level.


21st July 2018, Ainsdale Dunes, Sefton Coast. Photo: © RWD
A few dangling submerged roots(?) on the left (the decayed leaf descending from the right). The submerged hollow stem broke as your Author pulled it out of the water, so the real roots are probably missing. The plant roots at submerged nodes, so there could be many places where the roots emerge. The roots are the most toxic parts of Water-dropwort plants, but the other parts are never too far behind in their toxicity - you cannot be too complacent about handling it roughly, the sap will contain toxic polyynes which can penetrate human skin. A little sap may not kill you, but it could make you ill. It is always better to err on the side of caution; for you know not how much of the toxins are present at the time of year you mis-handle it. It could be in innocuous amounts, or in a nocuous concentration.


Not to be semantically confused with : Hemlock (Conium maculatum) [another deadly poisonous umbellifer, but one which is not aquatic and is in a differing genus] nor to Dropwort (Filipendula vulgaris) [a plant belonging to the Rose Family]

No relation to : Dropwort (Filipendula vulgaris) [a plant with similar name belonging instead to the Rose Family].

Superficial resemblance to :
Parsley Water-Dropwort (Oenanthe lachenalii), but that is not pale-green or glaucous-green, does not have slightly bulging stems which narrow at the nodes and has deeper more obvious grooves/ridges/ribs on the stems. It also usually has more umbellets in an umbel and unlike Tubular Water-dropwort does have bracts beneath the main umbel (linear bracts). Also, the styles on Parsley Water-dropwort are short in comparison to the length of the fruits, rather than as long or longer than the fruits. At least on the Sefton coast Tubular water-dropwort seems to be usually accompanied by the similar Parsley Water-Dropwort (Oenanthe lachenalii)

Slight resemblance to : Corky-Fruited Water-Dropwort (Oenanthe pimpinelloides), Narrow-leaved Water-dropwort (Oenanthe silaifolia), Parsley Water-Dropwort (Oenanthe lachenalii) but the pinnate leaves of all three of these have narrow linear leaflets on at least some of the pinnate leaves, but not all.

Superficial resemblance to : Fine-Leaved Water-Dropwort (Oenanthe aquatica) but the lower submerged leaves are 3- to 4-pinnate and the upper leaves 2- to 3-pinnate and finely divided leaflets.

Uniquely identifiable characteristics

Distinguishing Feature : The constriction of the stem at nodes, the slight bulging of stem between nodes and the pale to glaucous green colour of the stems. The plant is without hairs.

No relation to : Tubular Corn-lily (Ixia paniculata) [a plant with a similar name belonging to a differing family].

Hemlock Water-Dropwort is the most toxic of all the Water-Dropworts and is a contender for the most poisonous plant in the UK. So, ipso facto, the other Water-Dropworts are less toxic, so your Author has grouped them all under his orange 'High Toxicity' rating rather than the red Severe Toxicity rating which Hemlock Water-Dropwort is under.

Tubular Water-dropwort is native and grows in wet places such as water-filled shallow hollows, ditches, marshes and fens.

A Tubular Water-dropwort from Sardinia has been analysed for toxins and found to contain Oenanthotoxin and DiHydroOenanthotoxin, both polyynes (aka polyacetylenes). These are instrumental in blocking the GABAergic responses in humans (and presumably most other animals?). Oenanthotoxin is extremely toxic; the LD50 for mice was found to be 0.58mg/kg. The LD50 of Oenantotoxin for man has not been determined (experimentation to find out would be unethical), but symptoms include nausea, diarrhoea, convulsions, seizures, tachycardia, mydriasis and rhabdomyolosis. Death is a distinct possibility for symptoms progress rapidly giving but an hour for any treatment to take effect. Oenanthotoxin is typically present in all Oenanthe species (Water-dropworts), but amounts may vary between species, time of year, the location within the plant studied (roots, stems, leaves, flowers, fruit, etc) and the growing conditions (both climatic and soil chemistry). The growing conditions may include the presence or absence of organisms detrimental to the plant, for if under attack it will then likely garner a greater quantity of toxins to help defend itself. There are very likely other toxic metabolites which the plant manufacturers, but presumably these pale into relative insignificance in the presence of the highly toxic polyynes. Hemlock Water-Dropwort has typically been found to contain a higher amount of the polyyne toxins than other Oenanthe species, but don't count on it!


  Oenanthe fistulosa  ⇐ Global Aspect ⇒ Apiaceae  

Distribution
 family8Carrot family8Apiaceae
 BSBI maps
genus8Oenanthe
Oenanthe
(Water-Dropworts)

TUBULAR WATER-DROPWORT

Oenanthe fistulosa

Carrot Family [Apiaceae]