Melanthium is a genus of herbaceous perennial monocots native to North America. They are closely related to Veratrum

Veratrum

Veratrum is a genus of coarse, highly poisonous perennial herbs of the Melanthiaceae family. In English they are known as the False hellebores or corn lilies. Members of Veratrum are known both in western herbalism and traditional Chinese medicine as toxic herbs to be used with great caution...

, and in fact are included in that genus by some authors. The distinction between Melanthium and Veratrum is based on various morphological

Plant morphology

Plant morphology or phytomorphology is the study of the physical form and external structure of plants. This is usually considered distinct from plant anatomy, which is the study of the internal structure of plants, especially at the microscopic level...

 traits, but it is not yet clear where the line is best drawn.

They contain alkaloid

Alkaloid

Alkaloids are a group of naturally occurring chemical compounds that contain mostly basic nitrogen atoms. This group also includes some related compounds with neutral and even weakly acidic properties. Also some synthetic compounds of similar structure are attributed to alkaloids...

s similar to those found in Veratrum and are thus assumed to be poisonous.

Species

• M. latifolium
  Melanthium latifolium
  Melanthium latifolium is a species of flowering plant in the Melanthiaceae known by the common names slender bunchflower and crisped bunchflower. It is native to the eastern United States, particularly in the Appalachian Mountains.This perennial herb grows from a bulb with a network of rhizomes....
  
   (Veratrum latifolium)
• M. parviflorum (Veratrum parviflorum)
• M. virginicum (Veratrum virginicum)
• M. woodii (Veratrum woodii)