Family Pittosporaceae
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. 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; 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 ultimate inflorescence unit 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 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; 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. |
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