Identification of probably a weed

[straush]

I planted some sweet peas and this came up. I assume it's a weed but any idea ? I just used soil from under some trees rather than bought compost.

[straush]

[gray1720]

It's a weed, alright - I have it on my allotment, it looks as though it'll turn into something interesting, but instead has weird flower heads like little grains of couscous. Sorry, no idea what it's called!

[saddad]

Sounds like something from "Chenopodia" if it develops those types of seed head... try googling "Fat Hen" and see if the pics look like your weed.

[gray1720]

Fat hen it isn't, but I think saddad has nailed the family - couscous turns out to not be such a bad description, as quinoa is a member! Yellowy-red tinge to the leaves, which is why it looks interesting, rather than the glaucous green of fat hen.

[straush]

thanks all - i will get rid of it and let hte sweet peas (hopefully) come up without the competition.

[gray1720]

I think its Chenopodium rubra

[Beersmith]

I think its Chenopodium rubra

I don't have a suggestion of my own, but thought the leaves in the photograph were too oval in shape (rather than palmate) to be a goosefoot variety. But my knowledge of botany isn't good enough to say for certain.

[Digeroo]

I am not convinced about the Chenopodium though it is a very large family.  I have several which appear on my allotment they arrive with the manure.  I think it is a flower seeding, I am thinking antirrhinum. 
I had chenopodium rubra last year, it is a pain it creeps along the ground and then pops up, and when you try and pull it up you only pull off one branch and the rest of the plant is still lurking.  So you track the plant back to the root and it is the very devil to pull up.   I actually found the flower heads were nice to eat they have a slightly salty taste.   
Chenopodium family come with various leave shapes the Oak leaved one is very attractive.  Until it suddenly shoots up to a metre or more in height.   Fat hen can do that trick too.