Friday, May 29, 2015

Spring 3e: Ash and Hickories

 Ashes and hickories are alike in having pinnate compound leaves--compound because each leaf is composed of leaflets, pinnate because these leaflets are arranged on either side of a leaf-stem, rather than fan-like as in Virginia creeper or marijuana.  (You can tell a compound leaf because the bud will be at the base of the whole thing, and all of it will drop off in the fall.)  But the leaves of ash are opposite each other on the twig, while hickories have alternate leaves.

The more I look, the more white ash trees I find around here.  Fraxinus americana is a majestic, tall, straight-trunked tree when it reaches its full growth, but not showy otherwise.  Only when I discovered a few little seedlings in the woods near mine, did I first realize there must be another nearby--it takes two to tango, after all, among plants just as animals.  Only this spring did I find a tree with a low enough branch to look at flowers close-up--before that I relied on binoculars or telescope, with indifferent success.  These close-ups come from two neighbors at the high school, the medium-range from a third tree, and the last couple from my own large tree. White ash is generally dioecious (trees either male or female); all pictured are male except for my own.  White ash nationwide is in grave danger from the introduced beetle, Emerald Ash Borer, which is spreading here from its point of introduction in the midwest.  EAB was reported from the Boston area last season, so it's either here, or will be this season.

Photos: May 1st, 8th (4), 11th,13th (my tree through telescope),
16th, and two of my tree.

Pignut hickory (Carya glabra) is common in the neighborhood and I have a couple of my own.

Photos: May 4th (2), 5th (2), 8th, 11th, 16th, 19th (2), 23rd (2) and 26th.
All but the third and fourth are from a single tree.

I know of no other shagbark hickory (Carya ovata) in the neighborhood, but the nuts it bore proudly last year prove there must be one--and probably close by, since hickories (like ashes) are wind-pollinated.  This tree is distinguished by bark that splits off the trunk in long, hard strips.  The tree threw me a curve a few days ago: after watching the prominent catkins for weeks for any sign of flowering, the tree suddenly shed spent male catkins in large numbers.  I was left to pore over old photos to see what I'd missed.  Only in a photo from the day before did I see a tell-tale lengthening of a catkin that presages flowering.  But flowering needs about a week!  I remain mystified.

Photos: May 1st, 4th, 5th, 7th, 11th, 13th,
16th, 19th, 21st, 23rd, 26th, and 27th.
  All are of the same branch. 

Almost done with Spring 3!  Last up is a grab bag of species noticed along the way.

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