Santalales


The Santalales are an order of flowering plants of eudicots. Well-known members of the Santalales include sandalwoods and the many species of mistletoes. The order has a cosmopolitan distribution, but is heavily concentrated in tropical and subtropical regions. It derives its name from its type genus, Santalum.

Overview

Many of the members of the order are parasitic plants, mostly hemiparasites, able to produce sugars through photosynthesis, but tapping the stems or roots of other plants to obtain water and minerals; some are obligate parasites, have low concentrations of chlorophyll within their shoots, and derive the majority of their sustenance from their hosts' vascular tissues.
Most have seeds without testae, which is unusual for flowering plants.

Classification

The APG IV system of 2016 includes seven families. As in the earlier APG III system, it was accepted that Olacaceae sensu lato was paraphyletic but new family limits were not proposed as relationships were considered uncertain., this seven-family division of the Santalales was explicitly accepted by the World Flora Online, and implicitly by Plants of the World Online, in that it accepted none of the extra families recognized by other sources. The seven families are:
When only these families are recognized, one possible phylogenetic relationship among them is shown below. Support for some of the nodes is weak, and at least two families, Olacaceae s.l. and Balanophoraceae s.l., are not monophyletic:
A summary of the circumscription and phylogeny of the Santalales published in 2020 used 20 rather than seven families. Olacaceae s.l. was divided into seven families, Balanophoraceae s.l. was divided into two, and Santalaceae s.l. into seven., the Angiosperm Phylogeny Website accepted the families resulting from the division of Olacaceae s.l. and Balanophoraceae s.l. but not those from the division of Santalaceae s.l.

  • Olacaceae s.l.
  • *Aptandraceae
  • *Coulaceae
  • *Erythropalaceae
  • *Octoknemaceae
  • *Olacaceae s.s.
  • *Strombosiaceae
  • *Ximeniaceae
  • Balanophoraceae s.l.
  • *Balanophoraceae s.s.
  • *Mystropetalaceae
  • Santalaceae s.l.
  • *Amphorogynaceae
  • *Cervantesiaceae
  • *Comandraceae
  • *Nanodeaceae
  • *Santalaceae s.s.
  • *Thesiaceae
  • *Viscaceae

    • Earlier systems

    In the classification system of Dahlgren, the Santalales were in the superorder Santaliflorae. The Cronquist system used this circumscription:
    • order Santalales