The families of flowering plants

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L. Watson and M. J. Dallwitz

Pittosporaceae R. Br.

Habit and leaf form. Trees, shrubs, and lianas; with coloured juice, or non-laticiferous; bearing essential oils, or without essential oils; resinous, or not resinous. Plants autotrophic. Self supporting, or climbing; sometimes stem twiners, or scrambling (sometimes spiny); Sollya twining anticlockwise. Mesophytic, or xerophytic. Leaves evergreen; alternate (usually), or whorled (sometimes, almost, towards the branch tips); usually spiral; ‘herbaceous’ (commonly soft), or leathery; petiolate; non-sheathing; gland-dotted, or not gland-dotted; aromatic, or without marked odour; simple. Lamina entire; pinnately veined; cross-venulate. Leaves exstipulate. Lamina margins entire (usually, or undulate), or serrate. Leaf development not ‘graminaceous’. Domatia never explicitly mentioned for the family.

Leaf anatomy. The leaf lamina dorsiventral (mostly), or centric (in a few species). Hydathodes absent (even from crenate blades). Stomata present; mainly confined to one surface (mostly, abaxial), or on both surfaces; paracytic (usually), or cyclocytic (rarely). Hairs present; eglandular, or eglandular and glandular; multicellular. Unicellular hairs branched, or simple. Multicellular hairs uniseriate; simple (but sometimes T shaped: see illustration). Lamina with secretory cavities (located outside the phloem, inside the bundle sheath). Secretory cavities containing resin; schizogenous. The mesophyll containing crystals. The crystals commonly druses. Minor leaf veins without phloem transfer cells (Pittosporum).

Axial (stem, wood) anatomy. Secretory cavities present (in secondary phloem, and sometimes in the secondary cortex); with resin. Cork cambium present; initially superficial. Nodes unilacunar (occasionally), or tri-lacunar (usually). Primary vascular tissues in a cylinder, without separate bundles; collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring.

The wood diffuse porous. The vessels very to moderately small; solitary, radially paired, in radial multiples, clustered, and in tangential arcs. The vessel end-walls oblique; simple. The vessels without vestured pits; with spiral thickening. The axial xylem with fibre tracheids, or without fibre tracheids; with libriform fibres, or without libriform fibres; including septate fibres (but the septa sometimes few). The fibres without spiral thickening. The parenchyma paratracheal (sparse, vasicentric). ‘Included’ phloem absent. The wood not storied.

Reproductive type, pollination. Plants hermaphrodite (usually), or polygamomonoecious (rarely).

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; when aggregated, in cymes, or in corymbs. The ultimate inflorescence units cymose, or racemose. Inflorescences terminal, or axillary; corymbs or thyrses. Flowers bracteolate (with two bracteoles); small to medium-sized, or large (often showy); regular; not resupinate; 5 merous; cyclic; tetracyclic. Free hypanthium absent.

Perianth with distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; polysepalous, or gamosepalous (sometimes basally connate); regular; not persistent; imbricate; with the median member posterior. Corolla 5; 1 whorled; polypetalous, or gamopetalous (usually, with a more or less distinct tube); imbricate; regular. Petals sessile, or clawed (the claws more or less connivent).

Androecium 5. Androecial members free of the perianth; sometimes weakly, basally coherent, or free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 5; isomerous with the perianth; oppositisepalous; laminar, or filantherous. Anthers dorsifixed, or dorsifixed to basifixed (being almost basifixed in Citriobatus); non-versatile; dehiscing via pores, or dehiscing via short slits, or dehiscing via longitudinal slits; introrse. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral. Tapetum glandular. Pollen grains aperturate; 3(–4) aperturate; colporate (sometimes ruporate); 3-celled.

Gynoecium 2(–5) carpelled. Carpels reduced in number relative to the perianth to isomerous with the perianth. The pistil 1 celled, or 2(–5) celled. Gynoecium syncarpous; synstylovarious, or eu-syncarpous; superior. Ovary 1 locular (usually), or 2(–5) locular (rarely, completely or incompletely). Gynoecium when bilocular, transverse; stylate. Styles 1; attenuate from the ovary; apical. Stigmas wet type; non-papillate; Group IV type. Placentation usually parietal; rarely (i.e. when plurilocular), axile. Ovules in the single cavity when unilocular, 5–100 (? — to ‘many’); 4–30 per locule (?); horizontal, or ascending; arillate, or non-arillate; anatropous to campylotropous; unitegmic; tenuinucellate. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral. Endosperm formation nuclear.

Fruit fleshy, or non-fleshy; dehiscent, or indehiscent; a capsule, or a berry. Capsules loculicidal. Seeds endospermic. Endosperm oily. Seeds winged (rarely), or wingless. Embryo tiny, but well differentiated. Cotyledons 2–5. Embryo achlorophyllous (2/2).

Seedling. Germination phanerocotylar.

Physiology, phytochemistry. Sugars transported as sucrose, or as sugar alcohols + oligosaccharides + sucrose (in different species of Pittosporum). Not cyanogenic. Polyacetylenes recorded (falcarinone). Alkaloids present (commonly), or absent. Anthraquinones detected (Pittosporum); polyacetate derived. Iridoids not detected. Proanthocyanidins absent. Flavonols present; kaempferol and quercetin. Ellagic acid absent (7 species, 2 genera).

Geography, cytology. Temperate to tropical. Old World tropics and Australasia. X = 12.

Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Araliiflorae; Pittosporales. Cronquist’s Subclass Rosidae; Rosales. APG 3 core angiosperms; core eudicot; Superorder Asteranae; campanulid; Order Apiales.

Species 200. Genera 10; Bentleya, Billardiera, Bursaria, Cheiranthera, Citriobatus, Hymenosporum, (Marianthus), Pittosporum, Pronaya, Rhytidosporum, Sollya.

Economic uses, etc. Edible berries (‘appleberry’) from Billardiera longiflora.

Illustrations. • Billardiera fusiformis: as B. linearis, Bot. Reg. xxvi, 3 (1840). • Billardiera heterophylla: as Sollya heterophylla, Bot. Reg. 1466, 1831. • Billardiera ovalis: Bot. Reg. 1719, 1835. • Pittosporum rigidum: Hooker, Fl. Novae-Zelandiae (1853). • Technical details (Pittosporum). • Technical details (Pittosporum). • Technical details, from Lindley (Cheiranthera, Pittosporum).

The descriptions are offered for casual browsing only. We strongly advise against extracting comparative information from them. This is much more easily achieved using the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG).

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 16th May 2016.’.