black root

noun

1

: any of several plants or their dark-colored roots: such as

a

: a perennial plant (Pterocaulon undulatus) of the southern U.S. that has large black rootstocks

b

: culver's root

c

: colicroot sense 1

d

: a common comfrey (Symphytum officinale) with the upper part of the stem and inflorescence densely hispid

2

: any of several plant diseases characterized by dark discoloration of roots: such as

a

: cotton wilt sense 1

b

: a disease of radishes, beets, and sugar beets caused by fungi (genus Aphanomyces) and producing brown or black lesions on the roots, deformation of the roots, and a damping off of seedlings

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