Unidentified arable weed

[clicka15]

Hi Everyone,

I found this interesting arable weed growing in a newly harvested wheat field on the Sussex south coast. I think it may be some kind of Orache or Purslane or similar, but I wondered if anyone out there could offer a definitive id...?



Note the slightly fleshy leaves:



And the flowers are rather basic and almost spurge-like:



Thanks and best wishes,

Steven.

[aeshna5]

Looks like Fat Hen, Chenopodium album to me which like most goosefoots + related oraches are very variable in their appearance. Fat Hen is often mealy when young.

[clicka15]

Hello Aeshna5,

I'm not convinced it's Fat Hen (Chenopodium album) because it is much more upright in character than my plant above, and the leaves of Fat Hen are more serrated.

It was one of the species I checked before posting the photographs, but unless it is variable enough to grow in a more rambling fashion, I reckon it is something related but different - possibly Nettle-leaved Goosefoot (Chenopodium murale), but the flowers are redish in this species and mine aren't.

Thanks and best wishes,
Steven.

[aeshna5]

The leaves aren't always serrated + I've seen plants like this. Stace states that Chenopodium are vegetatively extremely plastic especially in habit + leaf shape! To be honest for 100% ID you'll need to examine seed sculpturing with a lens. But my feeling is that it's Fat Hen- any other verdicts out here?

[wyevilla]

My immediate reaction was fat hen as it resembles plants growing in field margins near here. Would love to have an alternative id to compare them with.

[clicka15]

Hi Aeshna5,

Your description sounds reasonable enough, and there are no other takers, so I guess I'll go with Fat Hen. I did consider this before I posted anyway. It just doesn't totally convince me. I don't think I'll venture an id using the seed sculpturing!

You mentioned 'Stace', which I assume is a field guide. Can you give me some more detail?

Thanks again,

Steven.

[almostnormal]

hi. i'd go for fat hen as well although it looks a trifle squished to be absolutely 100% sure. but i see alot of this on the job, and its certainly what immediately popped into my head.

stace is a practical field guide with in depth plant keys and no pictures. its handy to have sometimes, but it can be a bit of a pain. the plant keys themselves are however superior to collins or rose. i occasionally use it if i can't figure a plant out from rose, but to be honest its a bit overkill for the enthusiastic amatuer, which is what i am when it comes to plants.

[aeshna5]

Originally Posted by clicka15

Hi Aeshna5,

Your description sounds reasonable enough, and there are no other takers, so I guess I'll go with Fat Hen. I did consider this before I posted anyway. It just doesn't totally convince me. I don't think I'll venture an id using the seed sculpturing!

You mentioned 'Stace', which I assume is a field guide. Can you give me some more detail?

Thanks again,

Steven.

Steve, Stace is the field botanists bible- there's the meaty New Flora of the British Isles (Cambridge Press) + a much smaller compact Field Flora of the BI which lacks the hybrids + some of the less common aliens. I think there may be an updated version on the way.

Don't expect lots of pretty pictures, though there are useful line drawings of critical species + some photos. Some basic botanical knowledge would be needed to make most of this book.

There is also a DVD based on this book with many photos + maps from BSBI Atlas called Interactive Flora of the BI.

[thunder]

I understand a third edition of Stace is imminent, which might mean the second edition gets reduced!

henrya

[brucemstrs]

I agree it would almost certainly be Fat Hen. The trouble is it is well known for showing 'morphological plasticity in response to soil fertility' It is also inclined to hybridise with related species, futher comlicating things. Positive ID is difficult from a photo.

[AlanS]

It is most certainly Fat Hen.

You'll notice that the main stem has been cut, presumably during harvesting, and this is why there are now these rather atypical side branches.

As I did my Ph.D. on arable weeds I claim some authority here, lol.

Alan

N.B. The 3rd edition of 'Stace' is indeed in preparation, but I would not say 'imminent' yet.

[clicka15]

Hi All (and especially AlanS).

Sorry to labour the point, but I wanted to share some further observations about Fat Hen. My photographs above show a bushy plant with red stems, growing on its own with no similar plants nearby. The leaves are not that serrated and the flowers are stumpy in appearance. Also, it is the same size now as when I first started this thread.

Compare these observations with the photographs below.

The entire plant, ~1m high:


Upright flower heads clustered around the stem:


From above with uniform leaf pattern:


These new photographs were taken about twenty metres away from the above specimen. This plant is one of a dozen identical plants that fit the Chenopodium album description exactly. There are no red stems, the plants are much more upright, the leaves are much more serrated and not as fleshy and the leaves and flowers are much more clustered around the stem than the original specimen.

Alan's hypothesis that the original plant had been a harvest casualty is entirely plausible, but these other specimens would have been caught up in the same harvest, but are still much more upright and the tallest specimens are three times the height of the original.

Are you all still satisfied that morphological plasticity is the most likely reason for the differences in appearance, or is it possible that this could in fact be a different species of Goosefoot or Orache?

I suppose there is always the chance that the original specimen could be a runt (what with its stunted appearance) and that it has been sent away from the other plants to grow on its own! Don't think I'll get many takers on that theory though!!!

Best wishes (and hope you're all enjoying the Bank Holiday)

Steven.

[AlanS]

Originally Posted by clicka15

.
.

Alan's hypothesis that the original plant had been a harvest casualty is entirely plausible, but these other specimens would have been caught up in the same harvest, but are still much more upright and the tallest specimens are three times the height of the original.

Are you all still satisfied that morphological plasticity is the most likely reason for the differences in appearance, or is it possible that this could in fact be a different species of Goosefoot or Orache?

I suppose there is always the chance that the original specimen could be a runt (what with its stunted appearance) and that it has been sent away from the other plants to grow on its own! Don't think I'll get many takers on that theory though!!!

Best wishes (and hope you're all enjoying the Bank Holiday)

Steven.

Thank you for accepting my hypothesis as being plausible. I will point out, though, that the cut main stem of the topmost plant is clearly visible in the photograph, so whatever the cause of the accident that has befallen it, the plant is showing atypical secondary growth. Its terminal meristem has gone; it has to grow by extension of the side branches. The other plants have not lost their main stems, so show normal growth.
Fat Hen varies (a lot!) in leaf shape and in presence/absence of anthrocyanin - the red pigment - and so we see some of this variation here.

The plants are NOT oraches. Oraches have separate male and female flowers (mixed in the same head) and the female flowers have two flap-like structures (bracteoles) that enlarge considerably in fruit. The flowers we see here have both anthers and stigmas and all have five sepal-like 'tepals' and no bracteoles - making them a Chenopodium.

Chenopodium is a difficult genus, with each species variable, and there some around that can resemble Fat Hen, Chenopodium album, quite closely. The best identification characters are provided by the seeds. Nevertheless, all the photographs here are very typical C. album.

Alan

[clicka15]

Hi Alan.

Thanks for the quality information. It has been most helpful and an education.

I went back to check the original plant after you suggested it had been caught up in the harvest and there was clearly a scar where the main stem had been removed.

So Chenopodium album it is!

With thanks and best wishes,
Steven.