We can assume, that a plant with poisonous roots also has poisonous leaves, the stalk, flowers and juice. One such example is the grain combustion, which you just need to touch, so that blisters appear on the skin. There are, however, exceptions to this rule. Some plants' roots and rhizomes, deadly poisonous raw, they become
edible after cooking. If you are not sure, whether you have correctly recognized the plant, don't eat her.

Plants with poisonous roots

Cassava (Manihot)
Root tubers of this plant raw are deadly poisonous. Before consumption, they must be through 48 hours soaked in water, then cooked.

Trumpet narcissus (Narcissus)
Incorrectly called a daffodil, it can be easily recognized by the yellow trumpet flowers. If there is no flower, better not to touch the plant.

Mud floss (Calla)
Also called calla, it has very distinctive flowers. They are actually white on the inside, green from the outside. It grows in the forest swamps of Eurasia and North America. The roots of this plant can be eaten or ground into flour (see p. 92), but you have to cook it first. They are poisonous when raw. The rest of the plant contains toxins.

Collocation (colocasia)
It grows in humid areas throughout the tropics. Achieves 1,5 m in height, it has oblong leaves and yellow-orange flowers. Its large tubers are poisonous raw, however, after cooking, they can be eaten; they taste like potatoes.

Yam (Dioscorea)
Grown in subtropical and intertropical areas for its edible tubers. Some species, however, have poisonous tubers, when eaten raw. Because it's hard to tell them apart from the rest, it's best to always peel and cook them. The plant has large heart-shaped leaves, often grows next to tree trunks.

White-flowered hellebore (Cynanchum vincetoxicum)
It has a sharp end, heart-shaped leaves and small flowers. Eaten – the roots and pods induce vomiting, and hence – water loss by the body. This plant's milk juice is also toxic. It occurs in the countries of the temperate zone.

Snow (Ornithogalum)
This plant reaches a temperate climate 30 cm in height. Its bulbs are edible, but only after cooking. Other parts of the plant are inedible.

OTHER POISONOUS ROOTS
Wild potato tubers (Solanum) are suitable for eating, but only after cooking. In contrast, the tomato-like fruit of potatoes is poisonous. Wild tomatoes (Lycopersicon), whose fruits are edible, they look so much like potato fruit, that it is better to avoid some, i drugich. Zygadenus (Zigadenus) it has bulbs very similar to onions, but it is deadly poisonous. The underground parts of glaucoma are also deadly (Ranunculus), as well as the tuberous rhizome of the poisonous rage, also called hemlock (Hemlock).

It is very difficult to distinguish between poisonous roots, rhizomes and other subterranean parts of edible plants, therefore it is better to avoid eating them at all.