Santalales
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 Santalum haleakalae
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Santalales is an order of flowering plants, with a cosmopolitan distribution but heavily concentrated in tropical and subtropical regions.
Most have seeds without a testa, which is unusual for flowering plants. Many of the members of the order are parasitic plants, mostly hemi-parasites, able to produce sugars through photosynthesis, but tapping the stems or roots of other plants to obtain water and minerals; some (e.g. Arceuthobium) are obligate parasites, have low concentrations of chlorophyll within their shoots (1/5 to 1/10 of that found in their host’s foliage) and derive the majority of their sustenance from the host’s vascular tissues (water, micro- and macro-nutrients, and sucrose). Mistletoe is the common name for a number of parasitic plants within the order Santalales.
The APG II system of 2003 (unchanged from the APG system of 1998) uses the following circumscription:
- order Santalales
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- family Loranthaceae
- family Misodendraceae
- family Olacaceae
- family Opiliaceae
- family Santalaceae
The AP-Website indicates that Balanophoraceae should also be included in this order (post APG II). It also indicates that Olacaceae (sensu APG II) is not a good family and should be split. Furthermore, it indicates doubt about Santalaceae.
The Cronquist system (1981) used the following circumscription:
- order Santalales
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- family Medusandraceae
- family Dipentodontaceae
- family Olacaceae
- family Opiliaceae
- family Santalaceae
- family Misodendraceae
- family Loranthaceae
- family Viscaceae
- family Eremolepidaceae
- family Balanophoraceae
The families Viscaceae and Eremolepidaceae are included in the family Santalaceae by the APG. The genera Dipentodon (Dipentodontaceae) and Medusandra (family Medusandraceae) are regarded as unplaced by APG II (as is the family Balanophoraceae, now likely to be reincluded; see above). The family Medusandraceae consisted of two genera: Soyauxia and Medusandra. Molecular evidence place the former within the family Peridiscaceae of the order Saxifragales, and the latter within the order Malpighiales close to Passifloraceae-Turneraceae-Malesherbiaceae. The chinese monotypic genus Dipentodon is close to Tapiscia and is proposed to constitute the new order Huerteales with Tapisciaceae and the genus Perrottetia formerly placed in the family Celastraceae.
==References==
Soltis, Soltis, Endress & Chase (2005) Phylogeny and evolutioin of angiosperms. Sinauer Associates, Inc. Publishers, Sunderland, Massachusetts
Hawksworth, F., & D. Wiens (1996). Dwarf mistletoe: biology, pathology, and systematics. USDA For. Serv. Agric. Handb. 709. 409 p.
