Friday, June 17, 2011

An Overview of Ohio Dogbane and Milkweed Species (part 3 of 3): Telling Dogbane and Milkweed Apart.

Today is the third and final installment of my posts on milkweed and dogbane. I would now like to finish this segment by talking about how to tell dogbane and milkweed apart. Three years ago I moved to my current home. Upon my early biking trips, I noticed a patch of milkweed-looking plants. Being interested in monarch butterflies, I constantly was checking this patch to see if there were any caterpillars, but I never found anyway. Today, that patch of plants is still there, but I now know those plants to be dogbane, instead of milkweed. My goal this evening is to allow readers to go out and tell dogbane apart from milkweed.

The biggest similarity between milkweed and dogbane is that, if ruptured, a white, milky sap is released. The leaves of all dogbane and milkweed species share a similar vein pattern, one which the veins form a series of loops on both sides of the central vein. In clasping dogbane, Indian hemp, common milkweed, and Sullivant's milkweed, these loops are condensed, and form thin ovals. In the other milkweed and dogbane species, they are "rounder" in diameter. Lastly, If viewed from a distance, Indian hemp and clasping dogbane look a lot like common milkweed and Sullivant's milkweed.

Despite these similarities, there are some common differences that work for telling all species of dogbane apart from milkweed. The first difference I have is that dogbane tends to branch towards the top of the plant, where milkweed, excluding butterfly weed, will not branch. The stems of dogbane tend to be smooth, whereas milkweed generally has a hairy texture to the stem. Dogbane has a dark stem, where milkweed TENDS to have pale green stems. The flowers of dogbane form in flat clusters, where milkweed flowers form in ball shaped clusters.

Note the hairy stem of milkweed

Note the ball-shaped flower of milkweed

I will leave it off with that for tonight. Tune in tomorrow for information on wild geranium, a small plant found in the forest. Good Night.

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