What's this thing that appeared in my lawn?

Sometime in June a tubular shoot appeared in my lawn. I thought it might be an invasive weed so I dug it out, but I was curious so I planted it in a pot and have been growing it on. The leaves look a bit like Gentian Asclepsias but it appears not to have any flower buds, just little green shoots with tiny leaves. It had a fleshy root, rather like a Hosta. No more have appeared in the lawn and there's nothing like it in the area.
Has anyone any idea what it might be?
Photo attached:

 

No idea, but Welcome to Gardeners Corner

 

Welcome to GC, oldrose

My best guess is: ... it's a *thing*!

But, I'm sure more experienced gardeners will be along shortly.

Just wondering, are you UK based? Are you North/South/East/West somewhere inbetween? Which type of soil do you have? Sorry to bombard you with questions, but, they are all relevant in plant ID.

 

Hi, Thanks for your welcome.

I am in South Wales by the sea so the climate is generally mild and wet. The soil is gritty, slightly acidic, quite well drained and unusually dry at the moment. This was a long established lawn, not new turf.

Hope this helps!

 

Sorry, this doesn't help, but it reminds me of a work of art in the Millenium Gallery in Sheffield.

https://www.google.co.uk/search?q=b...a-ride%25E2%2580%25A6in-sheffield%2F;1280;960

Welcome to GC by the way

 

A couple of plants spring to mind Tree lily, Solomans seal.

A few more images with close up detail would be more helpful with identification

 

Hmm Don't think it is solomans seal although the leaf is similar.

 

Thanks. I think it's definitely not Solomon's seal which I'm quite familiar with. Will try to get some better pics. Most mysterious.

 

Here are some more images of the strange plant. Some of the leaves have gone brown because it has got a bit dry. I have separated it from the grass and repotted it, and will look after it for a bit, though my daughter is convinced it's something nasty.

There aren't any flowers other than tufts of tiny leaves, however I have spotted two tine buds amid the tufts (see closeup picture).

BTW, I didn't plant this. It either came in on a seed (perhaps dropped by a bird) or it was something planted by a squirrel. However, as you can see from the root picture, there is no bulb or rhizome. 22865[/ATTACH]

 

I'm no expert, but could it be......aaaarrrggghhh! Japanese knotweed?
If so, call in Quatermass!

 

I have no idea what it is, but it isn't Japanese Knotweed, the leaves are the wrong shape.

 

There you go - I knew I knew nothing..........Baby Triffid? Sorry! Couldn't resist it