Rosette (botany) - Form

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:

  • 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.
  • 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. 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.

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.

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