Scalesia
Encyclopedia
Scalesia is a genus in the family Asteraceae
endemic
to the Galapagos Islands
. It contains fifteen species displaying shrub or arborescent
habit. It is unusual because tree species are rare in Asteraceae.
All of the species have soft, pith
y wood.
Scalesia species have been called "the Darwin's finches
of the plant world" because they show a similarly dramatic pattern of adaptive radiation
.
Scalesia pedunculata is a large tree species which grows up to ten meters tall. They reach maturity in about fifteen years. The trees typically grow in stands of the same species and the same age. They die around the same time, and then a new generation of seedlings grow in the same place.
Scalesia atractyloides and Scalesia stewartii are two small tree species, very similar to each other.
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...
endemic
Endemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
to the Galapagos Islands
Galápagos Islands
The Galápagos Islands are an archipelago of volcanic islands distributed around the equator in the Pacific Ocean, west of continental Ecuador, of which they are a part.The Galápagos Islands and its surrounding waters form an Ecuadorian province, a national park, and a...
. It contains fifteen species displaying shrub or arborescent
Arborescent
Arborescent is a term used by the French thinkers Deleuze and Guattari to characterize thinking marked by insistence on totalizing principles, binarism and dualism...
habit. It is unusual because tree species are rare in Asteraceae.
All of the species have soft, pith
Pith
Pith, or medulla, is a tissue in the stems of vascular plants. Pith is composed of soft, spongy parenchyma cells, which store and transport nutrients throughout the plant. In eudicots, pith is located in the center of the stem. In monocots, it extends also into flowering stems and roots...
y wood.
Scalesia species have been called "the Darwin's finches
Darwin's finches
Darwin's finches are a group of 14 or 15 species of passerine birds. It is still not clear which bird family they belong to, but they are not related to the true finches. They were first collected by Charles Darwin on the Galápagos Islands during the second voyage of the Beagle...
of the plant world" because they show a similarly dramatic pattern of adaptive radiation
Adaptive radiation
In evolutionary biology, adaptive radiation is the evolution of ecological and phenotypic diversity within a rapidly multiplying lineage. Starting with a recent single ancestor, this process results in the speciation and phenotypic adaptation of an array of species exhibiting different...
.
Scalesia pedunculata is a large tree species which grows up to ten meters tall. They reach maturity in about fifteen years. The trees typically grow in stands of the same species and the same age. They die around the same time, and then a new generation of seedlings grow in the same place.
Scalesia atractyloides and Scalesia stewartii are two small tree species, very similar to each other.