What is a flower garden weed that is completely maroon with tiny yellow flowers?

Question:The weed is completely maroon. The leaves look like upside down hearts and are arranged in a "four leaf clover look-a-like "pattern. Instead of the leaf spread out flat, it hangs down thus making it look like an upside down heart. The stalk and leaves are solidly maroon in color.

Answers:
I believe you are describing Oxalis. There is an ornamental plant called: Oxalis regnellii atropurpurea, which is pictured in the link. There are many other oxalis, and lots of those are weeds. Further, some oxalis do bloom yellow. I have also seen pink blooms on plants with maroon foliage.