Tag Archives: Rhus typhina

A Few Michigan Galls

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Gall are formed by insects laying eggs or feeding on a plant. In response to this damage the plants produces growth hormones resulting in abnormal cell development. Galls normally occur during the plant’s most active growth time. Other parts of the plant remain unaffected.

Liposthenes glechomae

Creeping Charlie Gall on Ground Ivy

Creeping Charlie Gall (Liposthenes glechomae) is a grape-size gall that develops on Ground Ivy (Glechoma hederacea) which is also called Creeping Charlie or Gill-over-the-ground. The gall is formed when a cynipid wasp lays an egg in the leaf or stem of the plant. If you cut one of these galls open you will find a small white larvae. Cynipid refers to all members in the insect family Cynipidae. The wasp does no real harm to the plant so it cannot be used to control Creeping Charlie. Both the wasp and the weed are imported from Europe.

Acraspis erinacei

Hedgehog Gall on White Oak

Another Cynipid wasp gall is caused by the Hedgehog Gall Wasp ( Acraspis erinacei ). It was on a White Oak (Quercus alba) leaf. This is the agamic generation (they reproduce without males). The female generation emerges from this gall and lays her eggs in the leaf buds where they over winter. It is an interesting looking dime-sized gall.

Macrodiplosis quercusoruca

Vein Pocket Gall on Red Oak

The Vein Pocket Gall (Macrodiplosis quercusoruca) is caused by a larval stage of a gall midge in the family Cecidomyiidae. This gall was on Red Oak (Quercus rubra).

Melaphis rhois

Sumac Gall on Staghorn Sumac

Sumac Gall Aphid (Melaphis rhois) is one of the few aphids that cause galls to form. This one was on Staghorn Sumac (Rhus typhina). Staghorn Sumac Aphid is one of the woolly aphids. The galls are hollow and occur along the leaves.
Copyright 2016 by Donald Drife

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A Small “Big” Tree

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Staghorn Sumac Rhus typhina

Staghorn Sumac Girth

Staghorn Sumac Twig

Staghorn Sumac

Big tree hunting is a great sport. Many people find and report large trees but it is the largest of the normally small species that have always interested me. Record small tree species include a 5-inch diameter Witch-hazel, a 6-inch diameter Highbush-cranberry, a 7-inch diameter Red Elderberry, and an 11-inch diameter Pawpaw. Most people walk by trees that are less than a foot in diameter without ever thinking “big tree.”

Recently I found two large Staghorn Sumacs (Rhus typhina) on the campus of Oakland University in Rochester, Michigan. They are along Pioneer Drive southeast of Pawley Hall. The largest one is approximately one foot in diameter. Staghorn Sumac is a common species in Michigan that normally is just shrub size. It gets the name “staghorn” because the hair on the twigs resembles the velvet on the horns of a stag.

These two are not Michigan state champion size but are close. Champions are determined by a point system. The points equal the height in feet, plus the girth in inches (four-and-a-half feet from the ground), plus one-fourth of the average spread. The Michigan state champion Sumac scores 72 points. I measured the height of the largest Oakland University Sumac as 20-feet (by the stick method), its circumference at 4-feet above ground as 37-inches (the tree forks below the four-and-a-half-feet height) and its canopy spread at 26-feet x 23-feet. It scores 63 points. Currently there is no national champion Staghorn Sumac. National champions must be measured every ten years and our state champion’s data is older. The Oakland tree might qualify as a national champion.

The stick method to estimate tree height involves simple triangulation. You hold a straight stick perpendicular to the ground with your arm parallel to the ground and your hand level with your eye. The height of the stick above your hand must equal the distance from eye to the base of the stick. This forms a right triangle with two 45-degree angles. Position yourself so that when you sight over the top of the stick you see the top of the tree. The distance you are from the tree equals the approximate height of the tree.
The Michigan Botanical Club maintains the state’s big tree list and their website explains methods for measuring trees. The group American Forests maintains the national registry. 

You never know what you will find in the natural world by just keeping your eyes open.

Staghorn Sumac Rhus typhina

Two Large Staghorn Sumacs on Campus of Oakland University, Pawley Hall in Background

Note: Both of these trees have been removed. Updated 8/10/2021