White Twinevine Funastrum clausum – Native Plant of North America

Introduction

Funastrum clausum is sometimes classified under the name Sarcostemma clausum and goes by the common name of White Twinevine or Bejuco Revientachivo in Spanish. It is part of the Asclepiadaceae or Milkweed family, and like many members of this family, it exudes a milky latex. (Recently, the entire Milkweed family has been lumped into the Apocynaceae family, but I prefer to use the subfamily split of morphologically similar groups that help aid in identification). This is a beautiful but aggressive vine with lovely fragrant white flowers that are quite unique to the Milkweed family. If you live in an area where it is native, I encourage you to grow it in your yard. But if you live in the south and it is not native to your area, I do not advise planting it because of its aggressive nature. It could potentially become invasive.

Description of White Twinevine Funastrum clausum

Stem & Leaves

Funastrum clausum is a herbaceous perennial climbing vine that exudes milky latex. It grows from about 6-9 m long and climbs utilizing twining tendrils. The vines can become very aggressive, growing over trees, plants, and structures in their path.

The leaves are either attached directly to the stem (sessile) or have leaf stalks (petioles), and they are arranged oppositely on the stem. They are dark to medium green in color and are linear to oblong in shape, often with an acute to obtuse base. Leaves may be moderately to very pubescent and are somewhat succulent.

Funastrum clausum Flowers

The lovely fragrant flowers appear from spring till fall but can flower all year round. Flowers are borne in large umbels along the length of the stem. They have 5 pubescent white petals and they usually have a purple base that forms a conspicuous ring around the center of the flower. Sometimes the reddish-purple base is lacking, however.

As with all members of the Asclepiadaceae, the flowers have modified stamens that are formed into white globular lobes and united at the base into a ring-like structure. This makes identification of the genus quite easy as these are characteristic of the Funastrum genus.

Funastrum clausum Fruit

Its fruit is a follicle that is large, wide, and erect. When the follicle is ripe and dries, it splits open to release the seeds. Seeds are attached to a silky white pappus that is dispersed by wind.

Similar Species Funastrum clausum is Frequently Confused With

Funastrum clausum is generally not confused with other genera due to its unique flowers. However, it can be confused with other members of the same genus whose range overlaps. They can be differentiated as follows:

• Funastrum pannosum – this one is endemic to Mexico and shares a similar range. Its flower petals are more delicate in appearance, and the flower lacks the red ring around the center commonly found in Funastrum clausum.
• Funastrum cynanchoides – this one is found in the southern US and northeast Mexico only. It also lacks the red ring around the ring-like stamen structure that is often found in Funastrum clausum, and it has leaves with a cordate base instead of acute or obtuse. It also has red tinges on the edges of the petals lacking in Funastrum clausum.
• Funastrum heterophyllum is found in the southwestern US and throughout much of Mexico. It usually has reddish-purple petals instead of white, and its leaves are long and thin with a truncated base rather than acute or obtuse.

Distribution of White Twinevine Funastrum clausum

White Twinevine is found in the most southeastern corner of Texas, and it is also found in Florida. It is not found anywhere else in the USA, and it is not found in Canada.

In Mexico Bejuco Revientachivo is found in Baja California Sur, Sonora, Sinaloa, Nayarit, Jalisco, Colima, Michoacan, Guerrero, Oaxaca, Chiapas, Chihuahua, Durango, Nuevo Leon, Tamaulipas, San Luis Potosi, Puebla, Morelos, Veracruz, Campeche, Yucatan and Quintana Roo.

Funastrum clausum is also found throughout the Caribbean and in Central and South America as far south as northern Argentina.

Habitat & Growing Conditions of White Twinevine

Funastrum clausum grows in mildly acidic to alkaline soils.

Its water requirements are in the moist to mesic range. It requires some moisture but does not tolerate permanent flooding or arid soils, nor does it tolerate salt spray or brackish waters.

It is often found growing along swamps, rivers, riparian habitats, and moist woodlands throughout its native range.

White Twinevine grows in full sun to part shade.

It will not tolerate any freezing temperatures.

Growing White Twinevine in Your Garden

Funastrum clausum is best grown against a fence, arbor, or trellis of some kind.

Due to its aggressive nature, it can be difficult to control if the conditions are right for it. Do not grow it if it is not native to your area.

However, if it is native, it is a beautiful plant with fragrant flowers and provides important wildlife value.

Choose a location where it has support to climb on and will not be able to climb onto your other nearby vegetation. Vines can easily be cut to keep them under control if necessary.

Propagation is done by seeds collected from the flowers once ripe. Allow the seeds to fully dry before planting.

Propagation can also be readily done from herbaceous stem cuttings.

Wildlife Values of Funastrum clausum

White twinevine is a larval host plant for the Monarch, Queen, and Soldier butterflies. All of their caterpillars have adapted to feed on the plant and are not harmed by the toxic milky latex.

Native bees and wasps use the flowers as an important nectar source.

Status of Funastrum clausum

Bejuco Revientachivo is considered Globally Secure, G5.

In the USA, Funastrum clausum has not been ranked, as is the case with so many native species in the USA, even though it is only found in 2 states.

No information on its status could be found in Mexico, and it is not found in Canada.

Traditional or Other Uses of White Twinevine

Funastrum clausum Medicinal Uses

The milky latex of White twinevine is sometimes used to cure eye infections. In Jamaica, the plant was used as a remedy for colds.

In Costa Rica and Guatemala, the crushed leaves are used as a poultice to treat flesh-burrowing maggots of the Human Botfly.

White Twinevine as an Ornamental

This is a very easy plant to grow to the point it can become aggressive, and as such, it is at times popular as an ornamental. Once established, it requires no care other than occasional pruning to keep it under control.

Ethical Wildcrafting of Funastrum clausum

If you are harvesting Funastrum clausum from the wild, as always, use the 1 in 20 rule of Ethical Wildcrafting. Pick one in every 20 flowers, follicles, or leaves you see.

Wildcrafting and Processing

Picked fruits, leaves, flowers, or roots can be placed in a basket, bowl, or paper bag and brought home for processing. If you are harvesting multiple products on the same day, be sure to label the roots in a paper bag so that you do not confuse different plants.

To dry the leaves, simply place them on a rack or screen in a single layer and allow them to dry.

Roots should be brushed clean of any dirt and then chopped into more manageable pieces before drying. Dried roots are notoriously difficult to cut into smaller pieces once dried.

If you are wanting to dry the fruits, they will need to be cut into smaller pieces before drying to prevent rotting. Otherwise, they could also be dried more quickly in a food dehydrator on the lowest heat setting.

Once dried, the plant parts can be stored in a jar for later use.

Label your jar with the species’ name and the date of harvest. I also usually add the location of the harvest for my own reference.

Do not grind or crush the leaves or roots until you are ready to use them to keep them as fresh as possible and preserve their medicinal properties. When you pre-grind, even if stored in glass jars, this increases the oxidation rate and rapidly degrades the medicinal properties so that they are rendered ineffective in a shorter amount of time than if left as whole as possible.

When harvesting for propagation purposes, pick 1 in every 20 follicles you see. Make sure they are ripe when you pick them, and place them in a paper bag until they dry and split open. Once dried, the seeds are ready to plant. If using cuttings, simply cut from 1 in 20 vines you see. Keep the vines moist in a plastic bag with water or wrapped in a wet tea towel. Keep them cool until you get them home, at which time you can root them in water by immersing a node. Rooting hormones can also be used to encourage root production, although they should readily sprout roots from a node immersed in water without the use of hormones.

References and Resources

Canadensys Plant Search https://data.canadensys.net/vascan/search

Backyard Nature Newsletter https://www.backyardnature.net/yucatan/clausum.htm

Dictionary of Botanical Terms – by Lyrae’s Nature Blog https://lyraenatureblog.com/blog/dictionary-of-botanical-terms/

iNaturalist Plant Search https://www.inaturalist.org/home

NatureServe Explorer https://explorer.natureserve.org/Search

USDA Plants Database https://plants.sc.egov.usda.gov/home

Willis, Lyrae (Unpublished).  Plant Families of North America. 

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