Notes:

This is a common weed, but edible and highly nutritious.  It has fleshy, oval to spoon-shaped leaves and long, prostrate, light reddish-brown stems.  Small yellow flowers are borne in mid-summer, opening in the morning and closing up tight by late afternoon.  Without the flowers, it could be mistaken for Common Knotweed (Polygonum aviculare), but the lack of sheaths (ocrea) on the stems allows it to be distinguished with certainty.