The Santalales are an

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants t ...

s with a

cosmopolitan distribution In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The extr ...

, but heavily concentrated in tropical and subtropical regions. It derives its name from its

type genus In biological taxonomy, the type genus is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearing type of a nominal ...

Santalum ''Santalum'' is a genus of woody flowering plants in the Santalaceae family, the best known and commercially valuable of which is the Indian sandalwood tree, '' S. album''. Members of the genus are trees or shrubs. Most are root parasites w ...

'' (sandalwood).

Mistletoe Mistletoe is the common name for obligate hemiparasitic plants in the order Santalales. They are attached to their host tree or shrub by a structure called the haustorium, through which they extract water and nutrients from the host plant. ...

is the common name for a number of parasitic plants within the order.

Overview

Many of the members of the order are

parasitic plant A parasitic plant is a plant that derives some or all of its nutritional requirements from another living plant. They make up about 1% of angiosperms and are found in almost every biome. All parasitic plants develop a specialized organ called th ...

s, mostly hemiparasites, able to produce sugars through

photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in ...

, but tapping the stems or roots of other plants to obtain water and minerals; some (e.g. ''

Arceuthobium The genus ''Arceuthobium'', commonly called dwarf mistletoes, is a genus of 26 species of parasitic plants that parasitize members of Pinaceae and Cupressaceae in North America, Central America, Asia, Europe, and Africa. Of the 42 species that ...

'') are obligate

parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson h ...

s, have low concentrations of

chlorophyll Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words , ("pale green") and , ("leaf"). Chlorophyll allow plants to ...

within their shoots (1/5 to 1/10 of that found in their host's foliage), and derive the majority of their sustenance from their hosts' vascular tissues (water,

micro- ''Micro'' (Greek letter μ ( U+03BC) or the legacy symbol µ (U+00B5)) is a unit prefix in the metric system denoting a factor of 10−6 (one millionth). Confirmed in 1960, the prefix comes from the Greek ('), meaning "small". The symbol for ...

and

macronutrient A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excr ...

s, and sucrose). Most have

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosper ...

s without testae (seed coats), which is unusual for flowering plants.

Classification

The

APG IV system The APG IV system of flowering plant classification is the fourth version of a modern, mostly molecular-based, system of plant taxonomy for flowering plants (angiosperms) being developed by the Angiosperm Phylogeny Group (APG). It was published ...

of 2016 includes seven families. As in the earlier

APG III system The APG III system of flowering plant classification is the third version of a modern, mostly molecular-based, system of plant taxonomy being developed by the Angiosperm Phylogeny Group (APG). Published in 2009, it was superseded in 2016 by a fu ...

, it was accepted that Olacaceae ''sensu lato'' was

paraphyletic In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In ...

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 Plants of the World Online (POWO) is an online database published by the Royal Botanic Gardens, Kew. It was launched in March 2017 with the ultimate aim being "to enable users to access information on all the world's known seed-bearing plants by ...

, in that it accepted none of the extra families recognized by other sources. The seven families are: *

Balanophoraceae The Balanophoraceae are a subtropical to tropical family of obligate parasitic flowering plants, notable for their unusual development and formerly obscure affinities. In the broadest circumscription, the family consists of 16 genera. Alternati ...

Loranthaceae Loranthaceae, commonly known as the showy mistletoes, is a family of flowering plants. It consists of about 75 genera and 1,000 species of woody plants, many of them hemiparasites. The three terrestrial species are ''Nuytsia floribunda'' (the W ...

Misodendraceae ''Misodendrum'' is a genus of hemiparasites which grow as mistletoes on various species of ''Nothofagus''. Its species are all restricted to South America. The name of the genus is incorrectly spelt in a number of ways, including ''Misodendron'' ...

* Olacaceae * Opiliaceae * Santalaceae * Schoepfiaceae 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 The Angiosperm Phylogeny Website (or APweb) is a website dedicated to research on angiosperm phylogeny and taxonomy. The site is hosted by the Missouri Botanical Garden website and maintained by researchers, Peter F. Stevens and Hilary M. Davis ...

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.''

Earlier systems

In the

classification system Classification is a process related to categorization, the process in which ideas and objects are recognized, differentiated and understood. Classification is the grouping of related facts into classes. It may also refer to: Business, organizat ...

of Dahlgren, the Santalales were in the

superorder Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...

Santaliflorae (also called Santalanae). The

Cronquist system The Cronquist system is a taxonomic classification system of flowering plants. It was developed by Arthur Cronquist in a series of monographs and texts, including ''The Evolution and Classification of Flowering Plants'' (1968; 2nd edition, 1988) ...

(1981) used this circumscription: * order Santalales :* family Medusandraceae – sole genus '' Medusandra'' now in family Peridiscaceae, order Saxifragales :* family Dipentodontaceae – now in order Huerteales in APG IV :* family Olacaceae :* family Opiliaceae :* family Santalaceae :* family

:* family

Viscaceae Viscaceae is a taxonomic family name of flowering plants. In this circumscription, the family includes the several genera of mistletoes. This family name is currently being studied and under review as in past decades, several systems of plant tax ...

- sunk into Santalaceae ''s.l.'' in the seven-family system :* family Eremolepidaceae - sunk into Santalaceae ''s.l.'' in the seven-family system :* family

References

* *
Santalales on the Parasitic Plant Connection web page

NCBI Taxonomy Browser
{{Taxonbar, from=Q21851 Angiosperm orders