Excerpts from Jim Conrad's
Naturalist Newsletter

Purple Morning-glory, IPOMOEA PURPUREA

from the August 10, 2014 Newsletter issued from the Frio Canyon Nature Education Center in the valley of the Dry Frio River in northern Uvalde County, southwestern Texas, on the southern border of the Edwards Plateau, USA
PURPLE MORNING-GLORY

This week a genuine morning-glory sonata turned up in a pretty thicket of Cowpen Daisies next to the house of my neighbor Phred, shown above. Note the heart-shaped leaves. The vividly blue blossoms were about two inches across (5cm) with white eyes fringed with a kind of day-glow pale purple or lavender.

This species is not normally found growing wild in this part of the world, though that's what it seemed to be doing among Phred's wild daisies. However, last year Phred sowed around his house a package of seeds marketed as a "morning-glory mix." This resulted in lots of morning glories with flowers of various colors twining prettily among his sunflowers. I suspect that the ones we're looking at now must be "volunteers" from seeds that somehow traveled a few feet from their parent vines, and this year have been encouraged by Phred's frequent waterings of his wild daisies. As such, probably they're more "cultivated" than "wild growing."

Hundreds of viney species known as morning glories are scattered among various Morning Glory Family genera, and sometimes it can be hard to identify a plant to species. Therefore, to be sure about what you have, you must "do the botany." Below, you can see one of our flower's white, slender, funnel-shaped corolla tubes:

Purple Morning-glory, IPOMOEA PURPUREA, side view of corolla tube & sepals

A closer look at the calyx is shown below:

Purple Morning-glory, IPOMOEA PURPUREA, hairy calyx

In that picture we see that the slender sepals partly overlap one another and are of different lengths. Below, they bear long, sharp, upward-turned, white hairs. These are all important field marks needed to determine the species.

During the blossom analysis, I didn't forget to pay attention to the pure beauty of the blossoms' colors. Just look at one view enjoyed below:

Purple Morning-glory, IPOMOEA PURPUREA, view down tube

A longitudinal section of a blossom reveals that not only are the five stamens of very different lengths, but also that the stigma at the tip of the long, slender style is more or less spherical, though somewhat flattened. You can see this below:

Purple Morning-glory, IPOMOEA PURPUREA, flower longitudinal section

Such a roundish stigma helps us peg our morning glory as a member of the genus Ipomoea, the largest and most important of the Morning Glory genera, comprising over 500 species, among which the Sweet Potato is a very important member.

All the above field marks, especially the heart-shaped leaves, sepal shape and disposition, the forward-projecting hairs and the blossoms' white "eyes" giving way to a bluish outer corolla, lead us to IPOMOEA PURPUREA, commonly known as the Purple, Tall, or Common Morning Glory. If you do an image search on "Ipomoea purpurea" you'll see that the species' blossoms come in several colors, from deep blue to purple to rose, pink and white. Cultivars with white flowers ornamented with colored stripes also are available. However, the basic field marks remarked on here remain the same throughout the many cultivars.

Ipomoea purpurea is native to central and southern Mexico, though it's found growing in gardens as well as in the wild across North America, often "escaping" just like it apparently has at Phred's. However, as soon as Phred stops watering, I'll bet his morning glories will disappear.