Pittosporaceae

Small trees and shrubs, resin canals transversing the bark.  Leaves evergreen with simple, entire, alternate, sometimes whorled, no stipules.  Flowers mostly regular, mostly bisexual, with a tendency to unisexuality.  Five free stamens, five petals, united at the base, often clawed, five stamens, ovary superior 2-5 fused carples, 2-5locules, placentation axillary or parietal.  Fruit a loculicidal capsule or berry.  All confined to Australia except Pittosporum. Part of the text on this page has been modified from Allan (1961).

 

Pittosporum

Trees or shrubs with alternate or whorled leaves.  Fruit a loculicidal capsule with 2-5 valves, usually numerous seeds, immersed in a resin-like fluid.  Capsules open when mature.  Pittosporum contains approximately 160 species, found in South Africa, Asia, Australia, Pacific Islands and New Zealand.  In New Zealand 20 or more endemic species (depending on taxonomic treatment).  Pittosporum is one of the genera most likely to be encountered in regenerating bush in New Zealand and several species are popular in gardens, especially as hedges.

 

Synopsis of New Zealand Pittosporum

  1. Development strongly heteroblastic, capsules 2-valved
    1. Finally a tree e.g., P. turneri, P. virgatum, P. obcordatum.
    2. Remains a shrub e.g., P. rigidum.
  2. Development monoblastic
    1. Flowers axillary and solitary, capsules 3-valved e.g., P. tenuifolium.
    2. Flowers terminal, umbelled or fascicled

1.      Inflorescence compound, capsules 2 valved e.g., P. eugenioides.

2.      Inflorescence of simple umbels or fascicles

                                                                                 i.        Capsules 3-4 valved e.g., P. crassifolium.

                                                                               ii.        Capsules 2-3 valved

a.     Epiphytic e.g., P. kirkii, P. cornifolium.

b.     Terrestrial e.g., P. umbellatum.

 

 

 

 

Pittosporum turneri.  A juvenile plant (left) which has small leaves and divaricating branching and a tree (right) that has the lower part with the juvenile form and the upper part with larger leaves and non-divaricating branching.

 

 


Different leaf sizes and shapes found in one population of Pittosporum virgatum.

 

 

Pittosporum obcordatum.  A tree (left) showing the two very different leaf shapes and sizes and branching patterns found on the same plant and a close up of the divaricating branching part (left), showing the wide branching angles and small leaves; the flowers have the typical Pittosporum flower structure, note the partially fused, clawed petals.

 

 

A Pittosporum rigidum shrub (left) showing the typical dense form produced by divaricating growth and a close up (right) on the dense divaricating branching and small leaves.

 

 


Close up of Pittosporum tenuifolium (kohuhu) foliage and solitary, axillary immature capsule.

 

 


Pittosporum eugenioides (tarata, lemonwood) leaves and flowers.  Note the distinctive yellow midribs of the leaves and the terminal compound inflorescences.

 

 

 

Pittosporum crassifolium (karo).  Flowers (left), these show the typical Pittosporum flower structure of partially fused, clawed petals and the dark red petal colour common in some of the New Zealand species.  Mature capsule (right), note how the capsule opens out to expose the dark seeds that are surrounded by a sticky, resinous fluid, this piture also shows how the undersides of the leaves of this species are covered in white tomentum.

 

 


Flowers and foliage of the shrub epiphyte Pittosporum kirkii.

 

 


Flowers and foliage of Pittosporum cornifolium showing the whorled leaf arrangement found in many Pittosporum species.

 

 

Pittosporum umbellatum, showing the characteristic inflorescence (left) structure after which this species is named and a close up of an individual flower (right).  Note that even though the flower is structurally bisexual the carpel is reduced indicating that this flower is functionally unisexual.

 

 

 

 

Keys

New Zealand Taxa

Allan, H.H. 1961: Flora of New Zealand, Volume I, Government Printer, Wellington.

Cooper, R. C. 1956: The Australian and New Zealand species of Pittosporum. Annals of the Missouri Botanical Garden 43: 87-187.

 

Small-leaved Taxa

Wilson, T. & T. Galloway 1993: Small-leaved Shrubs of New Zealand. Manuka Press, Christchurch.

 

 

References

Allan, H.H. 1961: Flora of New Zealand, Volume I, Government Printer, Wellington

Cooper, R. C. 1956: The Australian and New Zealand species of Pittosporum. Annals of the Missouri Botanical Garden 43: 87-187.

Hathaway, L.A. 2001: Phylogenetic relationships of the New Zealand Pittosporum (Pittosporaceae) inferred from ITS sequences of nrDNA.  Unpublished MSc thesis, University of Waikato.

Poole, A. L. & N. M. Adams 1994: Trees and shrubs of New Zealand. Government Printer, Wellington.

Webb, C.J., W.R. Sykes & P.J. Garnock-Jones 1988: Flora of New Zealand, Volume IV, DSIR Wellington.

Webb, C.J., P.N. Johnson & W.R. Sykes 1990: Flowering Plants of New Zealand. DSIR Botany Division, Christchurch.

Wilson, T. & T. Galloway 1993: Small-leaved Shrubs of New Zealand. Manuka Press, Christchurch.