Curly Maple is not actually a species, but a description of a figure in the grain—it occurs most often in soft maples, but is also seen in hard maples. It is so called because the ripples in the grain pattern create a three dimensional effect that appears as if the grain has “curled” along the length of the board. Other names for this phenomenon are: tiger maple, fiddleback maple and flamed maple.
  Unlike quilted maple, curly maple is most pronounced when the board is quartersawn, and the curls usually become much less pronounced in flatsawn boards. 
It is not completely clear what environmental conditions cause curly maple, but there are different grades of curly maple, which greatly effect its price. Ideally, the criteria for determining value is based upon: color (both uniformity and lightness—whiter is preferred), frequency of the curls (tight, closely-spaced curls are preferred), and intensity (more depth is preferred). Prices can range from just slightly more expensive than regular soft maple for lower grades of curly maple, to triple, quadruple, or higher for prices of the highest grades.