Wednesday, May 20, 2015

Spring 3b: Maples

Silver maple (Acer saccharinum) flowered very early-- at the same time as quaking aspen.  I place it here with other maples for comparison.  Red maple (Acer rubrum) bloomed more than a week later than silver maple, and sugar maple and Norway followed close behind.

 Red maple is the only maple around here that is typically dioecious--male and female flowers on separate trees.  Pictures are all of a young female tree.  [Whoops! so is ash-leaved maple, below.]

Silver maple April 29th, May 4th, 5th, 7th, 11th and 16th.

Red maple (always same twig) April 28th, 29th, May 4, 7th, 11th and 16th.

Sugar maple (Acer saccharum) flowers and leafs out at almost the same time--rather like Norway maple.  Sugar maple, like silver maple, is monoecious--having male and female flowers together on the same tree.  Unfortunately, there are no low twigs on any of the trees I monitor.

May 7th, 11th, 13th and 16th.
(Sorry for the contortions.)

Norway maple, an alien invasive introduced as a street tree, gets included because it is so common here.  Norway maple has rather confused flowers: a single flowers cluster may have some that are male, some female, and some that are both.   (Look in the early photos for the central styles of the female and the outer, powdery, pollen-bearing stamens of the males.)

Norway maple (Acer platanoides) May 4th (2), 5th (2), 11th, 13th and 16th.

Only well after flowering did I discover a few ash-leaves maples (aka boxelder) at the high school.  Unlike other maples, ash-leaved maple has compound leaves similar to the (unrelated) ashes.   This makes five species of maples in this area!

Ash-leaved maple (Acer negundo)
May 8th (3) and 14th (2).

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