External Morphology of Plants: Modifications of Roots, Stems, and Leaves

Comprehensive vocabulary flashcards covering the structural modifications of roots, stems, and leaves for storage, support, physiological roles, and vegetative reproduction.

Fusiform Roots

Modified taproots that store food and become thick and juicy, where the middle portion is thick and both ends taper gradually, as seen in Radish.

Conical Roots

Modified roots that store food so the main root becomes thick and juicy, characterized by a broad base at the top and a gradually tapering lower end, such as in Carrot.

Napiform Roots

Modified roots where the upper portion becomes rounded due to food storage, while the lower portion abruptly narrows and becomes thin, such as in Turnip.

Tubercular Tap Roots

Modified main roots that swell irregularly due to food storage without forming any definite or particular shape, such as in Mirabilis (Sondhya Maloti).

Tubercular Adventitious Roots

Adventitious roots that develop from nodes near the soil surface and swell up irregularly to store food and attain an indefinite shape, such as in sweet potatoes.

Fasciculated Roots

A cluster or bunch of adventitious roots where all members swell up irregularly due to the storage of food, such as in Asparagus and Dahlia.

Nodulose Roots

Modified adventitious roots that swell specifically at their tips for food storage, as found in Mango and Ginger.

Moniliform Roots

Adventitious roots that alternately swell and constrict along their length, giving a bead-like appearance, such as in Bitter gourd.

Prop Roots

Roots that emerge from the stem branches, grow downward into the soil, and become thick pillar-like structures providing mechanical support to heavy branches, such as in Banyan.

Stilt Roots

Roots arising obliquely from the lower nodes of weak stems that penetrate the ground tangentially to give extra support and keep the plant erect, such as in Screw pine.

Climbing Roots

Adventitious roots originating from the nodal regions of weak stems that enable the plant to cling onto another plant or support to climb, such as in Betel vine.

Aerial Roots

Specialized adventitious roots that hang in the air to absorb moisture directly from the atmosphere, such as in Orchid.

Parasitic Roots (Sucking Roots)

Roots developed by non-green parasitic plants lacking chlorophyll that penetrate into the host plant's tissues to absorb nutrients, such as in Gold creeper.

Respiratory Roots (Pneumatophores)

Branch roots arising from the main root that grow vertically upward out of saline and muddy coastal soil, possessing small pores to take in air, such as in Sundori and Goran.

Reproductive Roots

Roots modified to produce adventitious vegetative buds that take part in reproduction and develop into new plants, such as in sweet potatoes.

Stem Tuber

An underground stem that becomes rounded and swollen from storing food, bearing nodes, internodes, scale leaves, and axillary buds situated in cavities termed 'eyes', such as in Potato.

Eyes (of Potato)

Cavities located at the axils of scale leaves on a stem tuber that contain axillary buds capable of producing new plants under favorable conditions.

Rhizome

A thickened underground stem that grows horizontally parallel to the soil surface or erectly, bearing clear nodes, internodes, scale leaves, roots, and axillary buds for food storage and vegetative propagation, such as in Ginger and Turmeric.

Bulb

A highly reduced, small, convex underground stem with compressed nodes and internodes, surrounded by thick and juicy scale leaves that store food and obscure the stem, producing profuse fibrous roots below, such as in onion and garlic.

Corm

A large, more or less rounded underground stem with prominent nodes and internodes whose axillary buds in the axils of scale leaves grow laterally into daughter corms, such as in Amorphophallus (B. Ol).

Runner

A slender subaerial stem that originates from axillary buds at lower nodes and creeps horizontally along the soil surface to produce new plants, such as in Hydrocotyle (B. Thankuni), Oxalis (B. Amruli), and Cynodon (Durba).

Stolon

A specialized runner arising from the base of the plant that grows horizontally, curves down to root at the nodes touching the soil, and gives rise to new independent plants, such as in Arum (Man Kochu).

Offset

A subaerial stem modification found in aquatic plants where the internodes are thick, short, and dwarf in appearance, such as in Pistia (B. Teropana) and Eichhornia (B. Kochuripana).

Sucker

A subaerial stem branch developing from an axillary bud that grows horizontally underground before turning upward to emerge above the soil and form a new shoot, such as in Chrysanthemum (B. Chandramallika) and Bamboo (B. Bansh).

Phylloclade

A green, flattened aerial stem modified to synthesize food through photosynthesis, while its leaves are reduced to spines to limit water loss and provide defense, such as in Cactus (B. Phonimonosha).

Stem Thorn

A sharp, stout aerial modification of axillary buds that develops instead of vegetative leaf buds to provide plant defense, such as in wood apple (B. Bel), Lawsonia (B. Mehendi), and Maina Kata.

Stem Tendril

A thin, thread-like, spirally coiled aerial stem modification that aids climbing plants in securing themselves to external supports, such as in Passion flower and Harjora.

Bulbil

A modified round, ball-like axillary bud that stores food and functions as an organ of vegetative propagation in climbing plants, such as in Dioscorea (B. Chupri aloo).

Leaf Tendril

A modified leaf apex or leaflet that transforms into a sensitive, coiled spring-like structure used to cling to supports, such as in wild pea.

Food-Storing Leaves

Leaves that become thickened and succulent due to the accumulation of food and water reserves, such as in Onion, garlic, and Aloe vera.

Fly Traps (Insectivorous Leaves)

Leaves modified into hollow pitchers or bags with closing lids that trap insects and digest them to absorb vital juices, as in Pitcher plant.

Reproductive Leaves

Foliage leaves that develop adventitious buds along their margins which form roots and detach to develop into independent plants, as in Bryophyllum (B. Patharkuchi).

Leaf Spines

Leaves or parts of leaves that are modified into sharp, pointed, non-photosynthetic protective structures, such as in Lemon.

Scale Leaves

Thin, dry, membranous, or juicy scale-like modified leaves found on underground stems that protect apical buds and can store food reserves, as seen in potato, ginger, turmeric, and onion.