The birdseye figured grain in sugar maple (Acer saccharum): literature review, nomenclature, and structural characteristics

Little is known about the "birdseye" figured grain of sugar maple (Acer saccharum Marsh.). This paper clarifies and expands the discussion of birdseye sugar maple by describing the similarities and differences with figured grains in other species, as well as discussing important features of its peculiar anatomy. Sections are also provided that discuss the proposed causes of the birdseye grain, detail birdseye sugar mapleʹs geographic distribution, and address what is known about genetics and birdseye maple. Possible variations on the birdseye theme (e.g., roundeye, fingernail, catʹs paw, distorted) are documented, and a new set of descriptive terminology is established. Finally, further observations and speculations on the birdseye phenomena are provided, and research directions are suggested.