Just popped up

Farendwoman

this has just popped up in my daughter's neglected pot of cinnamon basil which she has had on her windowsill from last year. The small seedlings are definitely cinnamon basil, but the  tall one clearly isn't.

Hortum-cretae

One of the cress family like shepherd's purse or pepperwort. 

H-C

Farendwoman

A weed then! Thanks h-c

pretty though!

Dave Hedgehog

Hortum-cretae says:

One of the cress family like shepherd's purse or pepperwort. 

H-C

See original post

Good ID!

Would definitely go with Pepperwort because of the incredile height and rounded seedpods.