Rosette (botany)

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dandelion
Ricciocarpos natans
.

In botany, a rosette is a circular arrangement of leaves or of structures resembling leaves.

In flowering plants, rosettes usually sit near the soil. Their structure is an example of a

internode gaps between the leaves do not expand, so that all the leaves remain clustered tightly together and at a similar height. Some insects induce the development of galls that are leafy rosettes.[1]

In bryophytes and algae, a rosette results from the repeated branching of the thallus as the plant grows, resulting in a circular outline.

Taxonomies

Many plant

Blechnum fluviatile or New Zealand
Water Fern (kiwikiwi) is a rosette plant.

Function in flowering plants

Often, rosettes form in

succulents.[2] (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
.

Protection

Rosette of leaves of Agave americana

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 genus

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.[4][5]

Form

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:

  • lanceolate.[6]
  • opposite leaves on the stem.[6] 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 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.[2]

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

See also

References

  1. Wikidata Q99657406
    .
  2. ^ a b Botany online: Features of Flowering Plants – Leaves
  3. ^ shows many images Archived 2008-07-05 at the Wayback Machine
  4. ^ 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.
  5. ^ Smith, Alan P.1979. Function of dead leaves in Espeletia schultzii (Compositae), and Andean caulescent rosette species. Biotropica 11: 43-47.
  6. ^ a b Botany online: Features of flowering Plants – Rosettes – Whorls
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