Tap Roots and Fibrous Roots

They are primary roots which give rise to several lateral roots or secondary roots. Tap roots divide, become fleshy and travel deep into the soil. Tap roots are seen to be present in perennial herbs like Quercus sps., Citrus sps., Daucus carota, and Taraxacum officinale, so on.

Fibrous Roots

These roots do not have a separate primary root. They have numerous small thread like roots that are similar in size and originate from the stem base. Fibrous roots spread on the soil surface instead of entering deep and straight into the soil. Fibrous roots are seen in grasses and in some shrubs.

Fleshy Roots

The fleshy roots are the storage places for food. They store excess food during the winter and adverse conditions such that the plant can make use of the food for its regrowth process. Some of the plants that come under this category are carrot (Daucus carota), turnips (Brassica rapa), beet root (beta vulgaris). These plants have tap root or main root storing the food. The secondary roots are transformed into tubers in the case of plants like sweet potatoes (Ipomea batatas) and Dahlia sps.

Aerial Roots

The aerial roots are formed in many of the land plants as well as in water plants. They are formed in the moist atmosphere. The aerial roots allow the climbers like Philodendron sps., to take the support of the host. The aerial roots in the epiphytes like orchids not only take the support of the host plants but, will absorb water from the air. The aerial roots are fleshy in many cases as they store water transforming into reservoirs.

Knees

The pneumatophores are developed in the plants like Taxodium distichum also called as Bald Cypress. The ground or water, cuts off the air from the roots and make the trees to develop knees. These knees are protruding on the surface allowing the plant to take in air.