What is this crochet stitch?
Looks like a double crochet three together (dc3tog).

It's commonly used as a decrease stitch but in this case there are likely a chain or two on each side leaving the space for the two maroon single crochets.

It looks like a complex stitch but it's really just three unfinished half crochets that then get finished all at once. Working through it once or twice should be all you need if you're comfortable with double crochets in general. 

The steps are:


  Step 1: Yarn over.
  Step 2: Take tip of hook insert into next st in row.
  Step 3: Yo hook and draw yarn through st. (3)
  Step 4: Yarn over and draw through two loops on hook.
  Step 5: Yarn over.
  Step 6: Take tip of hook insert into next st in row.
  Step 7: Yo and draw through stitch.
  Step 8: Yarn over and draw through two loops on hook.
  Step 9: Yarn over.
  Step 10: Take tip of hook insert into next st in row.
  Step 11: Yo and draw through once more (5 sts on hook).
  Step 12: Yo and draw through 2 loops on hook (4sts on hook).
  Step 13: Yo once more and draw through all 4 sts on hook.  


The link above also includes a video tutorial.

Note, that for the pattern above, steps 6 and 10 would be the same space rather than the next stitch as they're being worked in a chain space rather than in stitches.