Rosette (botany)

Rosette (botany)

In botany, a rosette is a circular arrangement of leaves, with all the leaves at a single height.

Though rosettes usually sit near the soil, their structure is an example of a modified stem.


Often, rosettes form in perennial plants whose upper foliage dies back with the remaining vegetation protecting the plant. Another form occurs when internodes along a stem are shortened, bringing the leaves closer together, as in lettuce and dandelion and some succulents. [ [ Botany online: Features of Flowering Plants - Leaves ] ] (When plants such as lettuce grow too quickly, the stem lengthens instead, a condition known as "bolting".) In yet other forms, the rosette persists at the base of the plant (such as the dandelion), and there is a taproot.


Part of the protective function of a rosette like the dandelion is that it is hard to pull from the ground; the leaves come away easily while the taproot is left intact.

Another kind of protection is provided by the "caulescent rosette" which is part of the growth form of the giant "Espeletia" genus in South America, which has a well-developed stem above the ground. [ [ shows many images] ] In tropical alpine environments a wide variety of plants in different plant families and different parts of the world have evolved this growth form characterized by evergreen rosettes growing above marcescent leaves. Examples where this arrangement has been confirmed to improve survival, help water balance, or protect the plant from cold injury are "Espeletia schultzii" and "Espeletia timotensis", both from the Andes. [ [ Goldstein, G. and Meinzer, F.1983. Influence of insulating dead leaves and low temperatures on water balance in an Andean giant rosette plant. "Plant, Cell & Environment" 6: 649-656.] ] [ [ Smith, Alan P.1979. Function of dead leaves in "Espeletia schultzii" (Compositae), and Andean caulescent rosette species. "Biotropica" 11: 43-47.] ]


Many plant families have varieties with rosette morphology; they are particularly common in Asteraceae (such as dandelions), Brassicaceae (such as cabbage), and Bromeliaceae. The fern, "Blechnum fluviatile" or New Zealand Water Fern ("Kiwikiwi") is a rosette plant.


The rosette form is the structure, the relationship of the parts, and the variations within it, as shown in the following study from a herbarium:

*"Dryas octopetala" (White Dryas, Rosaceae) has a leaf rosette of leaf blades with a short petiole, slim, egg-shaped leaves with cordate bases with clearly and regularly toothed margins, and single flowers on usually long peduncles or stalks, two to four centimetres across. The flowers have seven to nine, often even more, white egg-shaped petals. The sepals are lanceolate. [ [ Botany online: Features of flowering Plants - Rosettes - Whorls ] ]
*"Silene nutans" (Nottingham Catchfly, Caryophyllaceae) shows ensiform-lanceolate leaves. The slightly rosette-like ground leaves are bigger and of different shape than the sparse, opposite leaves on the stem. [ [ Botany online: Features of flowering Plants - Rosettes - Whorls ] ] This is explained in that side shoots with greatly prolonged internodes may spring from rosettes. They have one or more flowers at their tip, like the primrose. Especially in biennial plants, the main shoot can, too, grow with prolonged internodes and even branch. It is not unusual that the leaves of the rosette and those of the shoot differ in shape. [ [ Botany online: Features of Flowering Plants - Leaves ] ]

As form then, "rosette" is used to describe plants that perpetually grow as a rosette and the immature stage of plants such as some ferns.

ee also

**Bird's Nest Fern
**Ostrich Fern
**Wild Bird's-nest Fern


Wikimedia Foundation. 2010.

Игры ⚽ Поможем решить контрольную работу

Look at other dictionaries:

  • Rosette — can refer to:*Rosette (design), a small flower design, especially used in antiquity *Rosette (decoration), a small circular device that can be awarded with medals *A type of award ribbon *The AA Rosette, a mark awarded to fine restaurants by the… …   Wikipedia

  • Rosette (design) — A rosette is a round, stylized flower design, used extensively in sculptural objects from antiquity. Appearing in Mesopotamia and used to decorate the funeral stele in Ancient Greece. Adopted later in Romaneseque and Renaissance, and also common… …   Wikipedia

  • rosette — /roʊˈzɛt / (say roh zet) noun 1. any arrangement, part, object, or formation more or less resembling a rose. 2. a rose shaped arrangement of ribbon or other material, used as an ornament or badge. 3. an architectural ornament resembling a rose or …  

  • Crepis tectorum — Narrowleaf hawksbeard flower Scientific classification Kingdom …   Wikipedia

  • Grassette de Moran — Pinguicula moranensis Pinguicula moranensis …   Wikipédia en Français

  • Pinguicula moranensis — Pinguicula moranensis …   Wikipédia en Français

  • Pinguicula moranensis — Pinguicula moranensis …   Wikipédia en Français

  • Pinguicula moranensis — Taxobox name = Pinguicula moranensis image width = 275px image caption = In habitat in Oaxaca regnum = Plantae divisio = Magnoliophyta classis = Magnoliopsida ordo = Lamiales familia = Lentibulariaceae genus = Pinguicula species = P. moranensis… …   Wikipedia

  • Argyroxiphium — Taxobox name = Silversword image width = 250px image caption = Haleakalā silversword regnum = Plantae divisio = Magnoliophyta classis = Magnoliopsida ordo = Asterales familia = Asteraceae tribus = Heliantheae genus = Argyroxiphium genus authority …   Wikipedia

  • Verbascum blattaria — Panicle Scientific classification Kingdom: Plantae …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”