Pittosporaceae R. Br.
Habit and leaf form. Trees, shrubs, and lianas; with coloured juice, or non-laticiferous and without coloured juice; bearing essential oils, or without essential oils; resinous, or not resinous. ‘Normal’ 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. Leaves without a persistent basal meristem.
Leaf anatomy. Hydathodes absent (even from crenate blades). Stomata present; mainly confined to one surface, or on both surfaces; paracytic (usually), or cyclocytic (rarely). Hairs present; eglandular, or eglandular and glandular; multicellular. Unicellular hairs branched, or unbranched. Multicellular hairs uniseriate; unbranched (but sometimes T shaped).
Lamina dorsiventral, or isobilateral; with secretory cavities (located outside the phloem, inside the bundle sheath). Secretory cavities containing resin; Secretory cavities schizogenous. The mesophyll containing calcium oxalate crystals. The mesophyll crystals commonly druses. Minor leaf veins without phloem transfer cells (Pittosporum).
Stem anatomy. Secretory cavities present. Cork cambium present; initially superficial. Nodes unilacunar (occasionally), or tri-lacunar (usually). Secondary thickening developing from a conventional cambial ring. Xylem with fibre tracheids, or without fibre tracheids; with libriform fibres, or without libriform fibres (the fibres septate, but the septa sometimes few); with vessels. Vessel end-walls oblique; simple. Wood parenchyma paratracheal (sparse, vasicentric).
Reproductive type, pollination. Plants hermaphrodite (usually), or polygamomonoecious (rarely).
Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; in cymes, or in corymbs. The terminal inflorescence unit cymose, or racemose. Inflorescences terminal, or axillary; corymbs or thyrses. Flowers bracteolate (with two bracteoles); medium-sized, or large (often showy); regular; 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 well differentiated (tiny). Cotyledons 2–5. Embryo achlorophyllous (2/2).
Seedling. Germination phanerocotylar.
Physiology, biochemistry. Not cyanogenic. Polyacetylenes recorded (falcarinone). Alkaloids present (commonly), or absent. Iridoids not detected. Arthroquinones detected (Pittosporum); polyacetate derived. Proanthocyanidins absent. Flavonols present; kaempferol and quercetin. Ellagic acid absent (7 species, 2 genera). Sugars transported as sucrose, or as sugar alcohols + oligosaccharides + sucrose (in different species of Pittosporum).
Geography, cytology. Temperate to tropical. Old World tropics and Australasia. X = 12.
Taxonomy. Subclass Dicotyledonae; borderline Crassinucelli, or Tenuinucelli. Dahlgren’s Superorder Araliiflorae; Pittosporales. Cronquist’s Subclass Rosidae; Rosales. APG (1998) Eudicot; core Eudicot; Asterid; Euasterid II; Apiales. Species 200. Genera 10; Bentleya, Billardiera, Bursaria, Cheiranthera, Citriobatus, Hymenosporum, (Marianthus), Pittosporum, Pronaya, Rhytidosporum, Sollya.
This family exemplifies the well known difficulties in distributing certain Dicot families between Dahlgren’s Araliiflorae and Corniflorae. It is equally hard to assign them with confidence to the higher level groupings Crassinucelli and Tenuinucelli. This is interesting, given that the latter evidently represent a major divergence in the Dicot line of descent (cf.Young and Watson 1970, Chase et al. 1993).
Economic uses, etc. Edible berries (‘appleberry’) from Billardiera longiflora.
Illustrations. • Technical details (Pittosporum). • Technical details (Pittosporum). • Technical details (Cheiranthera, Pittosporum).
Cite this publication as: ‘L. Watson and M. J. Dallwitz (1992 onwards). The Families of Flowering Plants: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 14th December 2000. http://biodiversity.uno.edu/delta/’. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993, 1995, 2000), and Watson and Dallwitz (1991) should also be cited (see References).
