JOE-PYE-WEED [in America]

Eupatorium cannabinum

Daisy & Dandelion Family [Asteraceae]  

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Pappus: pappusZpossible (short)
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24th June 2006, canalside. Photo: © RWD
Spreads near watercourses where it is very common. Grows to 1.5m high.

19th July 2005, River Lathkill, Alport, Lathkill Dale, Derbyshire. Photo: © RWD
Straight stems often reddish-brown, sometimes branched. Lanceolate leaves im two sets of opposite threes up the stem, looking like whorls of six.

31st July 2007, Gait Barrows, Cumbria. Photo: © RWD
An 'umbel' of flowers atop each stem similar to those of Common Valerian or Ice-Plant. The flowers are in dense trusses. Leaves in tiers up the stem.

31st July 2007, Gait Barrows, Cumbria. Photo: © RWD
Growing in a limestone gryke. Flowers pink in bud open to sprout numerous long white stigmas. Umbel similar to that of Common Valerian.

20th July 2013, Litherland Leeds & L/pool Canal, Merseyside. Photo: © RWD
Some plants are branched.

30th July 2004, Audenshaw, Ashton Canal. Photo: © RWD
Young plants may have leaves in opposite pairs, triplets still to form.

12th Aug 2005, Lydiate, Leeds & Liverpool Canal. Photo: © RWD
Numerous reddish-pink buds going white at the ends.

30th July 2004, Audenshaw, Ashton Canal. Photo: © RWD
The central flowers open forest sprouting long white stigmas.

4th Aug 2009, Rufford Canal, Lancs. Photo: © RWD
The pseudo-umbel from the side is not really an umbel since the flower stalks do not start from one point. It is instead a compound subcorymbose panicle, of which there are many per plant.

4th Aug 2009, Rufford Canal, Lancs. Photo: © RWD
Each individual flower is tubular, with a very short flared end bearing five pinkish petals. Enshrouding the flower are long, purple-tipped sepal-like bracts. The corolla is tubular, never opening.

31st July 2007, Gait Barrows, Cumbria. Photo: © RWD
Two long white stigmas emerge from each flower.

4th Aug 2009, Rufford Canal, Lancs. Photo: © RWD
Five petals, the barely visible single style has 2 long stigmas which protrude well beyond the flower to make a haze over the inflorescence.

30th July 2011, Moses Gate Country Park, Gtr M/cr. Photo: © RWD
An isolated single disc-floret containing five five-petalled florets showing the pink/purple outer bracts and the rest of the flowers. Stigmas protrude from disc-florets which are themselves surrounded by long white hairs. The white hairs will become the simple pappus (or parachute) will bear the black seed on the wind.

17th Aug 2007, Cromford Canal. Photo: © RWD
The leaves are either 3-lobed or 5-lobed, or pinnate, all with very short stems, a pair of three's on opposite sides of the stem. Leaves slightly toothed.

Only the lower leaves have the typical 3- or 5-lobed hemp-type leaves, which are in opposite pairs ; the upper leaves are just single oval in opposite pairs. All leaves are oval, pointed and toothed and similar to those of Hemp (Cannabis sativa), hence the name.

No relation to : Agrimony [a plant with similar name]. Nor is it, despite the name, related to Hemp nor to Cannabis, which refers more to the shape and pattern of the leaves than to any psychotropic substances. Nor to Bifid Hemp-Nettle, Common Hemp-Nettle, Large-Flowered Hemp-Nettle or Red Hemp-Nettle since Hemp-nettles belong to the Mint and Dead-nettle Family.

Grows beside freshwater such as streams, canals, fens and in damp woods. Sometimes in drier places.

Uniquely identifiable characteristics

Distinguishing Feature : The leaves in opposite pairs of three with the umbel of pinkish-red flowers atop.

Hemp-agrimony is a hemicryptophyte, meaning the flower buds start off on or near the soil surface like they do in Dandelion. Like Dandelion, the seeds are borne by the wind on a pappus, or parachute.

Hemp-agrimony contain the poisons Euparin, some sesquiterpene lactones including Eupatoriopicrin and several Pyrrolizidine Alkaloids such as the non-toxic Viridiflorine, Cynaustraline plus the toxic PA's: Supinine, Amabiline, Lycopsamine, Echinatine, Intermedine and Rinderine. Euparin is a benzofuran or benzopyran which is phytotoxic and inhibits electron transfer in chloroplasts, which suggests that the plant has some internal use for it.

Viridiflorine and Cynaustraline are stereoisomers of each other, the difference between the two only being the position of the H-atom on the squiggly bond; whether it is above or below the plane of the pyrrolizidine rings. It differs from Amabiline only in the lack of a hydroxyl group on the pyrrolizidine rings and in an =O instead of a CH2. Both Viridiflorine and Cynaustraline are non-toxic. However, both Amabiline and Rinderine are.

All parts of the plant are poisonous, ingestion of which results in tremor, delirium and death. Pyrrolizidine Alkaloids will alkylate DNA molecules, and are therefore mutagenic and carcinogenic.

  Eupatorium cannabinum  ⇐ Global Aspect ⇒ Asteraceae  

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JOE-PYE-WEED [in America]

Eupatorium cannabinum

Daisy & Dandelion Family [Asteraceae]  

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