Interesting maple leaf

[Richard Jensen]

One of my students and I came across a red maple (Acer rubrum) leaf that
has an intresting morphology: essentially, there are two separate leaf
blades at the apex of the petiole (but neither has the shape of a typical
mature red maple leaf and they are essentially mirror images of each
other)

I wonder if this is an atavism suggesting that the ancestral leaf form was
compound, e.g, like the leaves of box elder (Acer negundo).  My
understanding is that the modern simple leaves of Prunus (cherries,
plums, etc.) are derived from compound leaves and I wonder if the same has
been suggested for maples.

Richard J. Jensen      |   E-MAIL: rjensen at saintmarys.edu
Dept. of Biology       |   TELEPHONE: 219-284-4674
Saint Mary's College   |   FAX: 219-284-4716
Notre Dame, IN  46556  |