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Qjurious
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3-666.56.00
Pittosporaceae
English: Pittosporums; Cheesewoods.
Botany: 10 genera; 200 species; trees, shrubs, lianas; tropical to temperate;
Region: Australia; Indomalaya, Asia, Oceania, Africa.
Genera: Auranticarpa, Bentleya, Billardiera, Bursaria, Campylanthera, Cheiranthera, Citriobatus, Marianthus, Pittosporum, Rhytidosporum.
Use: ornamental; fish poison; fruits for food.
Content: triterpenoid saponins; monoterpenes, sesquiterpenes, diterpenes, alkanes; polyacetylenes, C15-acetylene is common, falcarinone, falcarinol acetylene; benzyl acetate, coumarins, furanocoumarins; sesquiterpene lactones, acetate-derived anthraquinones, chlorogenic acids, quinic acids; quercetin, kaempferol, flavonols; C18, C20, and C22 fatty acids.
Lacking: iridoid compounds, ellagic acids, gallic acids, proanthocyanidins, petroselinic acid.
Taxonomy
Carlquist 1981 proposed a rosid affinity supported by the trichomes. But Pittosporaceae have secretory canals, unitegmic ovules, and lack ellagic and gallic acids
Van Tieghem already in 1884 proposed a close relationship to Apiaceae and Araliaceae, supported by root anatomy, the schizogenic secretory canals, the distribution and development of lateral roots and the unitegmic ovules
Takhtajan (1997) followed Van Tieghem.
Pax 1891 and Cronquist disagreed as Pittosporaceae have a different floral structure, superior ovary.
Erbar and Leins (1995, 2004) followed Van Tieghem, based on the similar early sympetaly, the dorsal, basal position of the gynoecial nectary, and the gynoecial development as being only gradually different, the lack of iridoids, the presence of falcarinone polyacetylenes. But Pittosporaceae are no secretory canals, and lack petroselinic acid.
Chase (1993) and Nicolas and Plunkett (2014) DNA sequence data, analysis of the chloroplast gene rbcL confirmed van Tieghem’s hypothesis. The data show that Pittosporaceae belong to a clade together with Apiaceae, Araliaceae and Myodocarpaceae, being sister to a clade formed by the other three families.
Stevens (2001) lists several characters supporting this clade: the typical development of lateral roots, absence of iridoids, presence of ethereal oils and schizogenous secretory canals.
In the Apg3 and Apg4 classification Pittosporaceae is a Family in Apiales.
Plant theory
In the Plant theory Araliales is split off from Apiales. Pittosporaceae is in Araliales in Phase 5 and Subphase 6.
Botany
Evergreen trees, shrubs or climbers with resin-ducts in the bark, rarely spiny.
Leaves: alternate, often crowded at the ends of the branches, simple, entire, dentate or lobed, ± leathery; stipules absent.
Flowers: few to many in terminal and/or axillary panicles or cymes, sometimes in clusters on the old wood or solitary in the axils, regular or rarely slightly irregular, hypogynous, bisexual or functionally (rarely morphologically) unisexual.
Androecium: stamens 5, alternate with petals, free or with somewhat connivent filaments; anthers dithecous, introrse, opening by slits or pores.
Pollen: tricolporate, 2–3-nucleate, exine, more or less reticulate with little sculpturing.
Gynoecium: ovary superior, sessile or shortly stipitate, paracarpous, with 2–5 carpels and parietal placentas, usually unilocular but sometimes 2–5-locular by central contact of placentas; style simple with capitate or somewhat lobed stigma.
Calyx: sepals 5, free and imbricate at least in bud, or somewhat connate.
Corolla: petals 5, imbricate in bud, generally free, rarely with slightly connivent claws.
Fruit: berry or a capsule with generally entire valves.
Seeds: without an aril but often covered by a viscid resin, rarely dry and winged; testa thin and smooth; endosperm copious and horny; embryo minute.
Literature
Carolin, R & Bittrich, V; Pittosporaceae; in Voy. Terra Austr. 2: 542 (1814), by Flinders.