NODDING BUR-MARIGOLD

Bidens cernua

Daisy & Dandelion Family [Asteraceae]

month8jul month8july month8aug month8sep month8sept month8oct

status
statusZnative
 
flower
flower8yellow
 
inner
inner8brown
 
morph
morph8actino
 
petals
petalsZ0 petalsZmany
(many)
type
typeZclustered
stem
stem8round
 

18th Sept 2008, Failsworth, Rochdale Canal. Photo: © RWD
Growing in a partially drained canal bed. Up to 2 feet tall with serrated leaves in opposite pairs. Flowers are mostly without ray florets 9but some speciens do have them, unlike London Bur-Marigold).


18th Sept 2008, Failsworth, Rochdale Canal. Photo: © RWD
Flower heads larger than London Bur-Marigold, and drooping as a result. Stalkless leaves.


18th Sept 2008, Failsworth, Rochdale Canal. Photo: © RWD
Unlike London Bur-Marigold not all flower heads are without rayed florets (but this specimen is).


18th Sept 2008, Failsworth, Rochdale Canal. Photo: © RWD
Leaves toothed like Trifid Bur-Marigold and not untoothed as is London Bur-Marigold.


18th Sept 2008, Failsworth, Rochdale Canal. Photo: © RWD
A single flower head perches atop each branched flowering stem. Behind this are seven to eight long narrow un-toothed bracts whereas in London Bur-Marigold there are about six.


18th Sept 2008, Failsworth, Rochdale Canal. Photo: © RWD
The serrated un-stemmed leaves are in opposite pairs.


18th Sept 2008, Failsworth, Rochdale Canal. Photo: © RWD
The bracts of the heavier nodding flowerheads are splayed backwards and thus upwards.


18th Sept 2008, Failsworth, Rochdale Canal. Photo: © RWD
The disc florets are more numerous than those in London Bur-Marigold. Note the green stripes mostly on the inner yellow bracts.


18th Sept 2008, Failsworth, Rochdale Canal. Photo: © RWD
This specimen has eight long bracts.


18th Sept 2008, Failsworth, Rochdale Canal. Photo: © RWD
Within the inner yellow bracts with green stripes lie the disc florets, which are also striped.


18th Sept 2008, Failsworth, Rochdale Canal. Photo: © RWD
The lower leaves have two (or two pairs) of petioles at the stalkless base where leaf meets stem.


Not to be semantically confused with : Branched Bur-Reed or Un-branched Bur-Reed nor with Burdocks such as Lesser Burdock (Arctium minus) nor with any of the Burnets such as Great Burnet (Sanguisorba officinalis) nor Bur Chervil (Anthriscus caucalis) or Pirri-pirri-bur (Acaena novae-zelandiae) [plants with similar names from different families]

Lookee-Likees : London Bur-Marigold but that has leaves without serrations and smaller non-drooping flower heads. Also similar to Trifid Bur-Marigold which does have serrated leaves, but that has lower leaves lobed in threes. Of these three, only Nodding Bur-Marigold might have ray florets on some specimens.

No relation to : Branched Bur-Reed nor with Un-branched Bur-Reed. And although they are in the Same Daisy Family, neither are they related to Marigolds such as Common Marigold which is in a differing Genus. [plants with similar names].

Nodding Bur-Marigold is more common than is London Bur-Marigold and grows beside fresh water, and in the margins of dry ponds, canals and reservoirs.

A POLYACETYLENE (POLYYNE)

Phenylheptatriyne (PHT) or 1-phenylhepta-1,3,5-triyne, is a poisonous phototoxic polyacetylene found in species of Beggartics and Bur-Marigolds of the Bidens genera such as London Bur-Marigold, and also found in species of the Dahlia genera, Blue Fleabane (Erigeron acris) and Tall Fleabane (Erigeron annuus) also contain PHT in the essential oils extracted from the roots as a major component (27 -37%), exceeded only by the c.50% concentration of Matricaria Ester. On exposure to UV light it is a phototoxic to bacteria and is also a fungicide and exhibits properties against cancer that may prove useful. It is very similar to Pontica Epoxide found in Yarrow (Achillea millefolium) but closes the benzene ring and lacks an epoxide group.


  Bidens cernua  ⇐ Global Aspect ⇒ Asteraceae  

Distribution
 family8Daisy & Dandelion family8Asteraceae

 BSBI maps
genus8Bidens
Bidens
(Bur-Marigolds)

NODDING BUR-MARIGOLD

Bidens cernua

Daisy & Dandelion Family [Asteraceae]

WildFlowerFinder Homepage