''Sigmoidotropis speciosa'' is a

leguminous Legumes are plants in the pea family Fabaceae (or Leguminosae), or the fruit or seeds of such plants. When used as a dry grain for human consumption, the seeds are also called pulses. Legumes are grown agriculturally, primarily for human consum ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

in the family

Fabaceae Fabaceae () or Leguminosae,International Code of Nomen ...

that originates in

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

and

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

Description

The purple, non-fragrant, invasive flowers of the "''Phaseolus giganteus''" are said to have snail or snail-shell shaped flowers, hence the origin of the common name. The multicolored, fragrant, non-invasive flowers of the ''Cochliasanthus caracalla'' are said to have corkscrew or

nautilus A nautilus (; ) is any of the various species within the cephalopod family Nautilidae. This is the sole extant family of the superfamily Nautilaceae and the suborder Nautilina. It comprises nine living species in two genera, the type genus, ty ...

-shell shaped flowers, hence the origin of that common name. Though some claim that the leaves of one species are darker and differently sized compared to the leaves of the other, it is difficult to distinguish between these two plants through foliage alone. There have been multiple instances where both plants have been grown side by side for years and the discovery that they were not the same species was made only after the less mature plant finally bloomed. It is said that both plants are pollinated by ants so, without ants, the plant will produce few, if any, seeds,. The snail vine, ''Phaseolus giganteus'', is delightfully fragrant.
"discusses characteristics of each in detail" Flowers are a solid, pale purple. The flowers, which grow alone or in small groupsAlmost Eden Snail Vine
"Description, growing, and sale information" rather than in clusters, consist of four petals: one large wavy half-circle on the top, two tear-drop shaped petals that point inwards, and a thin, erect, curly petal sprouting from the center of the flower. Depending on the angle, the two bottom petals can appear to be a single petal that strongly resembles the large, upper petal. When this happens, the three main petals come together to form an open-clam shape. The center of the flower and the end of the thin, erect may have a small area of yellow and/or white but the color is usually faint and only noticeable upon close examination. Immature flower buds often form fat half-crescents but, unlike the corkscrew vine, these buds are green, yellow, or brown. This plant might be more susceptible to aphids but is definitely invasive and has been compared by multiple growers to

kudzu Kudzu (), also called Japanese arrowroot or Chinese arrowroot, is a group of climbing, coiling, and trailing deciduous perennial vines native to much of East Asia, Southeast Asia, and some Pacific islands. It is invasive species, invasive in ...

. Rapid growth combined with the ability of vines touching the ground to take root make this an invasive plant.The Snail Vine - Confusion Reigns Supreme
. "discusses characteristics of each in detail" This plant has been known to regrow even after all foliage visible above ground has died from frost.
. "description"

References

{{taxonbar, from=Q50870538 Faboideae Plants described in 2011 Flora of Mexico Flora of Belize Flora of Brazil Flora of Colombia Flora of Costa Rica Flora of Nicaragua Flora of Peru Flora of Venezuela