The two are:
A wild type from North India. This is the original undomesticated species. It flowers regularly, sets fertile seed, and is known as a "colonizer." Its rooting tends to be shallow, especially in the damp ground it seems to prefer. If loosed on the world, it might become a weed.
A "domesticated" type from South India. This is the vetiver that has existed under cultivation for centuries and is widely distributed throughout the tropics. It is probably a man-made selection from the wild type. It is nonflowering, nonseeding (or at least nonspreading), and must be replicated by vegetative propagation. It is the only safe type to use for erosion control.
It is not easy to differentiate between the two types—especially when their flowers cannot be seen. Over the years, Indian scientists have tried to find distinguishing features. These have included differences in:
Stems. The South Indian type is said to have a thicker stem.
Roots. The South India type is said to have roots with less branching.
Leaves. The South India type apparently possesses wider leaves (1.1 cm vs 0.7 cm, on average).2
Oil content. The South India type has a higher oil content and a higher yield of roots.
Physical properties. Oil from the wild roots of North India is said to be highly levorotatory (rotates the plane of polarized light to the left), whereas that from the cultivated roots from South India is dextrorotatory (rotates polarized light to the right).
Scent. The oils from the two types differ in aroma and volatile ingredients.
Whether these differences are truly diagnostic for the two genotypes is as yet unclear. However, at least one group of researchers consider that the two vetivers represent distinct races or even distinct species. 3 Perhaps a test based on a DNA profile will soon settle the issue.
Like its relatives maize, sorghum, and sugarcane, vetiver is among the group of plants that use a specialized photosynthesis. Plants