Rosette

Rosette [ Botany - Biology - Pathology ]
Derivate form: Rosetting (Noun)

Dictionary of botanic terminology
index of names

BOTANY: A circular whorl of spreading or radiating basal leaves arising from a centre or crown at the base of a plant.

BIOLOGY: A group of organs, such as leaves or or leaf-like structure (e.g., petals, bracts, lobes, cells. etc.) clustered and radiating from a common point of attachment.

PATHOLOGY: Any of several plant diseases which result in such an abnormal cluster of leaves on a stem.

A succulent rosette
( Haworthia emelyae v. multifolia )

In botany a rosette is a circular or spiral arrangement of overlapping leaves growing at a shoot tip or on a shortened stem often at or close to the ground level. The leaves in a rosette are close together and arranged in a compact circular pattern or cluster that resemble the petals of a rose.

Plants with a rosetted stem often reproduce by forming new shoot at their base or in leaf axils. The new shoot can be separate from the parent plant after they have developed their own root system.

Succulent rosette [ Botany ]

A leaf succulent where leaves are symmetrically arranged in a rosette

( Echeveria lauii )

Many leaf succulents as Crassula, Haworthia and Sedum, exhibit rosette-type growth.

Rosette succulents capture the water that condense from nocturnal dew on the leaves of the rosette allowing the plant to survive for long period of drought.

Rosette ( Growth habit) [ Botany ]

A plant growth habit whereby leaves are symmetrically arranged, flattened and radiating from the crown or centre at the base of a stem with very short internodes.

This habit is habitual in biennials in their first year. In plants that form rosettes, the basal leaves are those that arise directly from the crown of the plant, and which often differ from leaves arising from the stem or on the floral scape.

In nature most epiphytes like bromeliads grow high on tree branches. They capture rain in the rosette formed by the leaves and absorb water and nutrients through specialized cells concentrated inside this rosette.

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Holdfast roots [ Botany ]
Dictionary of botanic terminology - index of names

Some species of climbing plants develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place.

Climbing plants, like the poison ivy (Toxicodendron radicans), Boston ivy (Parthenocissus tricuspidata), and trumpet creeper (Campsis radicans), develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place. Usually the Holdfast roots die at the end of the first season, but in some species they are perennial. In the tropics some of the large climbing plants have hold-fast roots by which they attach themselves, and long, cord-like roots that extend downward through the air and may lengthen and branch for several years until they strike the soil and become absorbent roots.

Major references and further lectures:
1) E. N. Transeau “General Botany” Discovery Publishing House, 1994