An abstract leaf or plume design. I've never seen these in anything other than green ice cream shaped bowls, although I've heard reports of aqua and marigold (see right column).

Bowls, 8-8 1/2 inches

Green, 205 (2009), 23, 38, 60, 85 (all 2010),
   55, 75 (both 2011)

Olive green, 225 (2001)

Above is one of two known Mayan bowls in marigold. This one sold in 2008 for $2,500. There was another sale of a ruffled marigold bowl in 2009 for $1,900.