Climbers and runners – The Ipomoeas

Geetha Iyer

Landscape artists, gardeners, or anyone who is fond of plants will tell you that climbers and runners are a charming group of plants that add beauty to bring about a creative difference to your spaces, be they indoor or outdoor. As the name suggests, these are plants that have a weak stem and therefore grow by climbing on to supports or by trailing on the ground. Many of the climbers that are now used prominently in landscaping and as indoor beauties were once wild plants. There are hundreds of plants that fall under this category, many of them sharing the same environment as us, yet are hardly noticed. I hope to bring to your attention some of these plants which require so little attention to cultivate and also contribute to the health of the environment and humans.

Plants of the genus Ipomoea are climbers or runners that have close association with several organisms including humans. It belongs to the family Convolvulaceae, which is recognized easily by its trumpet/bell shaped flowers. There are close to 700 species of Ipomoea found the world over. They are tropical sun loving plants that can flourish even in poor soils. Their association with humans would appear to be near complete, ranging from their use as ornamental, medicinal, and food plants to their use even in religious rituals. One of the properties of Ipomoea as well as other members of the family of Convolvulaceae is the presence of certain kinds of cells in its foliar and root tissues that store a compound the scientists refer to as ‘glycosides’. Seeds of Ipomoea species contain different kinds of alkaloids, some of them being neurotoxins to both humans and animals. For this reason herbivores generally avoid them, permitting them to flourish well to the point of becoming problematic weeds.

History will tell you that Ipomoea aquatica has been used as a vegetable by South Asians from as early as 300AD (some claim it to be in use since 200BC) and that these cultures were aware of its medicinal value. It is believed that the wild plant was domesticated by both Chinese and Indians. However, Europeans discovered this plant only in 1962 and recorded it for the first time from the Malabar coast. They then took it with them. Commonly called water spinach in English, this plant, native not only to Asia but also to Africa and Southwest Pacific islands, is found worldwide. Known as kalamba in Sanskrit, it is called puisaag or kalamai-saag in Hindi, neer-kuzhumi in Tamil and thota-kura in Telugu. Almost all South Asian cultures are aware of their medicinal properties and it was an important ingredient of food in places like Malaysia and Philippines. Considered a laxative, a tonic, in Philippines, an experimental attempt at using a mouthwash made from this plant appeared effective against bacteria such as E coli and S aureus. In Sri Lanka, this plant was part of the indigenous medicine to treat diabetes. There are several other medicinal properties this plant possesses. They are also a rich source of vitamins and minerals. The plant is seen in wetlands in many of our waterways. They grow so fast that in some places they are considered as weeds.

A more familiar vegetable of this genus in India is the Ipomoea batata or the well-known sweet potato. It is a native of Central America but is a crop plant cultivated and used world over for food. Along with having compounds that are antioxidants, sweet potatoes are a rich source of calories, proteins, and vitamins and rank very high in terms of nutritional value in America.

Ancient Aztecs and Zapotecs used Ipomoea extensively in their shamanic rites. Aztecs firmly believed that the Ipomoea seeds were a means to communicating with the Sun gods. A particular kind of alkaloids present in several species of Ipomoea are hallucinogenic and so were used to bring about a state of mind suitable,supposedly, for communion with the spirits and God! The wild variety of the well-known ornamental plant, I purpurea – Morning glory, and Ipomoea violaceae were used commonly for this purpose. Some Ecuadorian cutlures may have used Ipomoea carnea in the same way. Modern pharmacological studies have shown that the alkaloid in many of these plants is Lysergic acid amide and Lysergic acid hydroxyethylamide that are only slightly different chemically from the molecular structure of LSD, a known hallucinogen. An infusion of these Ipomoea species is said to produce rapid intoxication quickly leading to a hallucinogenic state. This ‘Ipomoea trance’ is believed to last up to three hours. However, no unpleasant side effects have been recorded.

A more common variety that is grown by the gardeners and can also be seen growing wild is Ipomoea nil. It is a climber with oovate and lobed leaf and is commonly called blue morning glory. This is often hybridised with I purpurea to produce differently coloured garden varieties.

Ipomoea campanulata is a large stout climber whose sturdy stems can twine around the large stems of trees to climb up to the top. The bell shaped flowers are pale violet in colour with a deep purple shade in the neck of their bells. Recently, a water soluble compound was isolated from its seeds that had properties similar to the commercial gums extracted from other plants. Efforts are on to see whether this gum could find commercial use.

The green pods of Ipomoea muricata, known as nityavazhutana in Malayalam, is used as a vegetable, cooked along with coconut to make a delicious curry.

Another commonly found species of Ipomoea is the railway creeper – Ipomoea cairica or I palmata – earning this epithet due to the fact that it is seen in areas around a railway station; it’s a very common species with its unmistakable purple flower and palmately lobed leaves. It very readily roots, when the nodes of the stems touch the soil. It is not particular about any soil type and so flourishes well in most places. It might serve well to bind soils and prevent its erosion. Some believe that the crushed leaves of this plant can bring about relief from rashes.

Running on the sand above the tide line is this beautiful widely distributed beach plant Ipomoea pes-carpae, With branches growing up to 33 feet in length, these plants found in the coastal areas form mats on the sand helping to prevent erosion and stabilize sand dunes. Like most of the Ipomoea species this too grows vegetatively from stem cuttings. They are quite tolerant to salts and high temperatures and have been recorded to have recovered well after storms and hurricanes.

One reason that Ipomoea species survive well is largely because they are avoided by many common herbivores. But not so the insects, which you can look out for on these plants. The bright coloured sap sucking jewel bug, the tortoise-shell beetle and grasshoppers can be frequently seen on them. Sphingid moth (hawk moth) caterpillars can be seen feeding on the Ipomoea plants. As the flowers do not contain the chemical concoctions of the leaves, the insects thrive by eating the flowers. At the same time there are also certain insects, such as the bees, butterflies, moths, wasps, ants, and flies that help to pollinate their flowers.

Of all medicinal uses that the Ipomoea species are said to provide, the one universally accepted is the use of their roots as a laxative to treat constipation.

Ipomoea for classroom
Besides studying all aspects of leaf morphology, Ipomoea is an excellent genus for learning about the family Convolvulaceae.

Ipomoeas grow from stem cuttings and grow well even in degraded soils: Investigate to learn about vegetative propagation by obtaining Ipomoea plants and growing them in the laboratory. Ipomoea cultivar varieties can be obtained from garden nurseries. But if one looks around, one is sure to find wild species, even in our cities. Some places to find them would be near railway stations. Ipomoea pes-caprae grows in plentiful in many of our beaches. Those of you from Chennai can see this plant at the Adyar beach near the estuary with the broken bridge. Other places have them too.

Studying the pollen grains of Ipomoea is a fascinating activity. Details to study pollen grains are available at: http://www.biologyeducation.net/classroom/thehidden-world-of-microorganisms-2/.

This is but an introduction to Ipomoea. Look out for these species, collect them, and bring them to your school to grow them. One does not need to buy expensive plants from the nurseries to add beauty and greenery to one’s school.

References
1. For Hallucinogenic notes: https://www.erowid.org/library/books_online/golden_guide/g131-140.shtml
2. Images of Ipomoea species from India: Flowers of India website http://www.flowersofindia.net/risearch/search.php?query=Ipomoea&stpos=0&stype=AND
3. Common Indian Wildflowers by Issac Kehimkar. Published by Bombay Natural History Society
4. Review of the genus Ipomoea: traditional uses, chemistry and biological activities by Marilena Meira et al,Brazilian Journal of Pharmacognosy, 22(3): 682-713, May/Jun. 2012

The author is a consultant for science and environment education. She can be reached at scopsowl@gmail.com.