Family Pennantiaceae

Pennantiaceae J.G. Agardh

~ Icacinaceae in former treatments

Habit and leaf form. Rainforest trees (to 30 m high, with buttressed, leaning trunk and characteristically zig-zagging branchlets (Australian P. cunninghamii), or shrubs, or lianas (rarely); non-laticiferous and without coloured juice. Self supporting, or climbing. Leaves alternate; not gland-dotted; without marked odour; simple. Lamina entire; pinnately veined. Leaves exstipulate. Lamina margins entire, or dentate (or lobed). Leaves without a persistent basal meristem. Domatia occurring in the family, or never explicitly mentioned for the family.

Leaf anatomy. Stomata paracytic. Hairs present. Multicellular hairs uniseriate.

Stem anatomy. Nodes tri-lacunar. Secondary thickening developing from a conventional cambial ring. Vessel end-walls commonly reticulately perforated, or scalariform (with thin and numerous bars). Primary medullary rays wide.

Reproductive type, pollination. Plants hermaphrodite, or dioecious, or polygamomonoecious. Female flowers with staminodes, or without staminodes. Gynoecium of male flowers pistillodial, or vestigial, or absent.

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; in cymes, or in panicles. The ultimate inflorescence unit cymose. Flowers regular; mostly 5 merous; tetracyclic. Free hypanthium absent.

Perianth with distinct calyx and corolla, or petaline (the calyx very small, rudimentary in P. cunninghamii); 5, or 10; 1 whorled, or 2 whorled; isomerous. Calyx if detectable, 5; 1 whorled; gamosepalous (into a tube); tubular; regular; persistent. Corolla 5; polypetalous, or gamopetalous; valvate; regular; white.

Androecium 5. Androecial members free of the perianth, or adnate (to the corolla tube); free of one another; 1 whorled. Stamens 5; isomerous with the perianth; oppositisepalous; alternating with the corolla members; filantherous. Anthers dorsifixed; latrorse, or introrse.

The pistil usually, 1 celled. Gynoecium syncarpous; synovarious, or synstylovarious, or eu-syncarpous (?); superior. Ovary 1 locular, or 2 locular. Gynoecium non-stylate, or stylate. Styles when present, 1, or 2. Ovules in the single cavity 2; when more than one-locular, 2 per locule; pendulous; arillate.

Fruit fleshy, or non-fleshy; indehiscent; a drupe. The drupes with one stone.

Physiology, biochemistry. Cyanogenic.

Geography, cytology. Australian and Antarctic. Temperate to tropical. Australia (E. Australia, Norfolk Island, New Zealand.

Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Corniflorae; Cornales. Cronquist’s Subclass Rosidae; Celastrales. APG 3 core angiosperms; core eudicot; Superorder Asteranae; campanulid; Order Apiales.

Species 4. Genera 1; Pennantia.

This inadequate description lacks information on informative “esoteric characters”, expecially anther development and embryology. As it stands, it offers no support for recent removal of this genus from Icacinaceae (Cornales or Celastrales), and does not effectively distinguish it from the present descriptions of either Icacinaceae or Celastraceae.

Economic uses, etc. Including cultivated ornamentals.

Illustrations.
• Pennantia cunninghamii: habit.
• Pennantia cunninghamii: leaves and inflorescence.