geff.2007's picture

Guernsey Fleabane (2)

Observed: 26th September 2013 By: geff.2007geff.2007’s reputation in Plantsgeff.2007’s reputation in Plantsgeff.2007’s reputation in Plantsgeff.2007’s reputation in Plantsgeff.2007’s reputation in Plants
Fleabane, Canadian (1)
Fleabane, Canadian (2)
Fleabane, Canadian (3)
Fleabane, Canadian (4)
Description:

Much branched plant with narrow alternate leaves and numerous small flower heads. Actually growing on the verge of the pavement so no appropriate habitat selected. Wikipedia says this used to be Erigeron Canadensis which is what iSpot tries to use but neither link to the common name.

Identifications
Species interactions

No interactions present.

Comments

geff.2007's picture

Many thanks for the comments

Many thanks for the comments lavateraguy - this is the second time down this path - see iSpot node 298852. I thought I might have got it right this time, especially with 3 agreements. Looking at other postings it appears to be very difficult to be accurate and the more detail, the more confusing. Rose states that Canadensis resembles Erigeron acer but with +-bristly hairs and that sumatrensis is more densely covered with grey-green soft hairs. 298852 certainly appears to be more hairy than the latest posting. With my non-botanical mind I think I will call them midatlanticus (halfway between Canada and Guernsey)!!!!! Look out for the next one.

lavateraguy's picture

I have it easy ...

... 99.9% of the Conyza up here are C. canadensis - otherwise I would likely be in the same position with Conyza as with Galinsoga, i.e. only recording to genus.

I can't tell definitely which one you have here. In the field you could try measuring capitula, or, after Rose, try identifying them by touch (bristly vs soft-hairy stems). At least you have the advantage of having the opportunity to compare them.

landgirl's picture

Leaf edges

According to Blamey, Fitter and Fitter, Conyza canadensis leaves are edged with straight hairs, while in C. sumatrensis the hairs are hooked. Sounds a useful discriminator - I've never met C. sumatrensis so can't speak from experience.

lavateraguy's picture

According to Stace ...

... this discriminator only applies to the proximal portion of the leaf margin; the distal portion of the leaf margin has curved hairs in both species.

geff.2007's picture

Thanks to you both - if the

Thanks to you both - if the weather improves I will take another look. Apparently another factor is that C.sumatrensis has easily snapped brittle stems C.canadensis doesn't.

Ambroise's picture

I don't think we can really

I don't think we can really tell from the pictures unforts (but like Lavateraguy I'm inclined to think it is not C. canadensis), and I'd recommend Sell and Murrell's key and descriptions in their Flora of Great Britain and Ireland. It is such a tricky group but it is worth the effort because more information about the distribution and the spread of the different species is needed (let alone their hybridisation).

geff.2007's picture

Thanks for the further

Thanks for the further comments and I will look sor Sell and Murrells key, Ambroise. In the meantime this has got me so intrigued that I found two more plants locally and at the risk of being boring will add them as an observation. It appears that neither plant has any sign of hairs on the leaves (I checked one out this morning) Neither does it snap cleanly so I wouldn't describe it as brittle. The flower heads seem more conical - if you are still following this thread I would welcome all your comments on the new posting.

landgirl's picture

Surprised...

..that the leaves are hairless. I've just had a close look at basal leaves from C. canadensis. They are lanceolate, 5-7 cm long, have an average of 2 teeth per side and are edged with hairs sticking out at right angles, some of which have a distinct hook. The hairs also appear on both upper and lower surfaces, which are a matt, fresh green. Poland suggests that basal leaves and stem leaves are different - not sure which you were looking at. However, mine don't match his description. I don't think C. sumatrensis has been recorded in my part of the country.

lavateraguy's picture

Fide bsbidb.org.uk C. sumatrensis appears to be established ...

... in Nottingham and Retford, with scattered records from other towns in Nottinghamshire and Lincolnshire, but is scarcer (2 records in Leicester and 1 in Peterborough) in Leicestershire and Northamptonshire. It was present in Kings Lynn, but hasn't been recorded there this decade.

[And it looks as if I should be looking out for it in Stafford.]

spins's picture

Hi, could very well be C. floribundus

To me, this is not C. sumatrensis. Having said that, those things are difficult to judge on photo. Many people get distracted by irrelevant information trying to ID Conyza. Here is how you do it (will work perfectly in more than 90 percent of all cases). C. bonariensis is much more reminiscent of Erigeron acer, so I don't include it. Look at a flowering plant (not too late in the season - best to avoid Conyza in winter, things tend to get blurred). If you clearly see very white projecting ligulate flowers, it's C. canadensis. This should be a very common plant, get to know it. If you see a Conyza that is not C. bonariensis with clearly larger flower heads than in C. canadensis, it is C. sumatrensis and if you see a Conyza without clearly projecting very white ligulate flowers and with flower heads as small as in C. canadensis, it is C. floribundus (beware of photographic effects if trying to ID a picture!). At the end of flowering, the projecting ligulate flowers in C. canadensis fall out, so can be overlooked, so you should always check the following (with care): If the inner phyllaries exactly reach the top of the flower heads, it is C. floribundus. In C. canadensis, the inner phyllaries are clearly shorter than the flower, in C. sumatrensis, they are slightly shorter. It can be difficult to see the inner phyllaries: just press the flower head gently between thumb and index finger and all will be revealed.

Cheers, spins.

spins's picture

Changed my mind

I now see that there are too much hairs on the phyllaries for it to be C. floribundus, so this must be C. sumatrensis, sorry for that. It is on the phyllaries of C. canadensis that hairiness is variable, the phyllaries of C. floribundus tend to be not obviously hairy, invariably. I had forgotten that, sorry.

Cheers, spins.