Tropical Plant Database - Plant Details

Pittosporum kauaiense is a tree that grows from 4-10 m tall. The young parts and inflorescences are covered in long, pale brown hairs although the branches can become smooth or the hairs are present only in scattered patches. The leaves are elliptic in shape meaning they are widest in the middle of the leaf and narrowing gradually to the tip and the base. They are 9-27 cm long and 3.5-11 cm wide and are fairly thin with the veins conspicuous as they are slightly sunken on the upper leaf surface and raised on the lower surface. Although the leaves have short sparse white hairs on the upper leaf surface they are quickly lost and the leaf surface becomes smooth. The short white to brown hairs on the lower surface are sparse but are retained during the lifetime of the leaf.
Ha'awa flowers are borne in inflorescences that develop from buds found in the leaf axils (at the base of the stalk that supports the leaf and the stem). By the time the inflorescences develop the leaves may have already fallen so the clusters of white flowers are conspicuous along the otherwise naked branch. A single Ha'awa tree will produce all male (pollen producing) or all female (ovule producing) flowers. Inflorescences are borne on a short stalk that is only 3-10 mm long and contain 7-13 flowers. Unlike other Pittosporum species the calyx of Pittosporum kauaiense does not form a tube but is made up of five distinct green sepals. The petals are white to cream and form a narrow tube (12-13 mm long) which encloses the stamens (pollen producing structures) or ovaries (ovule or egg producing structures). The fruit are dry, capsules that can be round or almost square in shape and are from 9-20 mm long. If many flowers are pollinated the resulting fruit may be densely packed within a single inflorescence stalk. The outer surface of the fruit contains several furrows that run from the top to the base of the fruit between which the fruit surface may be shallowly wrinkled.

These plants have been reported to be poisonous however details on the specific parts with toxic properties are not provided in the references identified.

(Merlin, M. 1999. Hawaiian Forest Plants. Pacific Guide Books, Honolulu, HI.)

Ten native and endemic Pittosporum species are found in Hawai`i. Pittosporum kauaiense is found only on Kaua`i in diverse mesic forest between 240-1,220 m elevations.
Pittosporum is a large genus containing 150 species with a distribution in tropical and subtropical regions of Australia, New Zealand, Malaysia, Africa, and numerous Pacific Islands. In the Pacific, Pittosporum is found in Fiji, New Caledonia, Tonga, Hawai`i, the Austral, Cook, and Society Islands.

(Carlquist, C. 1974. Island Biology. University of Columbia Press, New York.)
(Gemmill, C. E. C., G. J. Allan, W. L. Wagner, and E. A. Zimmer. 2002. Evolution of Insular Pacific Pittosporum (Pittosporaceae): Origin of the Hawaiian Radiation. Molecular Phylogenetics and Evolution 22 (1): 31-42.)

Pittosporum species are nectar producing and have fragrant flowers. Male and female flowers are produced on different trees in almost all of the native Pittosporum species and pollen is carried from male to female flowers by insect pollinators. Where the distribution of Pittosporum kauaiense and Pittosporum glabrum overlaps on Kaua`i these two species are able to successfully reproduce and the viable offspring have been observed that have morphological characteristics that are intermediate between the parent species. These individuals that are the result of reproduction between two different species are called hybrids.
Pittosporum seeds are bird dispersed and the current distribution of the genus throughout the Pacific may reflect long-distance dispersal events mediated either internally or externally by birds. Birds consume the seeds after the capsule opens and the seeds may also become attached to the bird by the sticky resinous coating of the seed.

The native Hawaiian Pittosporum species share the names H?'awa or H?'awa. The Hawaiian name of this species, Ha'awa lau nui, refers to the large leaves of this species that can be up to 27 cm long and 11 cm wide. The Latin name of the genus, Pittosporum, is derived from the Greek words "pittos", meaning pitch and "sporos" meaning seeds, in reference to the black seeds covered with a film of viscous resin.

(Plowden, C. C., 1970. A Manual of Plant Names, Philosophical Library, New York.)

The native Hawaiian Pittosporum species are considered to have diversified from a single colonization event into Hawai`i from a South Pacific origin. The Hawaiian species are most closely related to Pittosporum species from the South Pacific including species from Tonga and Fiji. Extensive morphological variation in leaf size, shape and fruit characteristics is found within native Hawaiian Pittosporum species. Study of the DNA of these species has found that in the markers studied there is no identifiable genetic divergence between these species.

(Gemmill, C. E. C., G. J. Allan, W. L. Wagner, and E. A. Zimmer. 2002. Evolution of Insular Pacific Pittosporum (Pittosporaceae): Origin of the Hawaiian Radiation. Molecular Phylogenetics and Evolution 22 (1): 31-42.)
(Carlquist, C. 1974. Island Biology. Univeristy of Columbia Press, New York.)

We currently have 60 herbarium specimens for Pittosporum kauaiense in our collection. Click on any specimen below to view the herbarium sheet data.

• 017464 - collected by Derral Herbst in 1971
• 017460 - collected by Derral Herbst in 1971
• 079947 - collected by Derral Herbst in 1973
• 017465 - collected by Steven P. Darwin in 1975
• 017462 - collected by Tim Flynn in 1981
• 017463 - collected by Tim Flynn in 1981
• 017461 - collected by Tim Flynn in 1981
• 010270 - collected by Tim Flynn in 1982
• 017458 - collected by Tim Flynn in 1984
• 017459 - collected by Tim Flynn in 1985
• 017457 - collected by Tim Flynn in 1985
• 017454 - collected by Tim Flynn in 1987
• 017456 - collected by David H. Lorence in 1987
• 001718 - collected by David H. Lorence in 1988
• 017455 - collected by Tim Flynn in 1988
• 033853 - collected by K. R. Wood in 1991
• 033852 - collected by K. R. Wood in 1991
• 012084 - collected by K. R. Wood in 1991
• 033851 - collected by K. R. Wood in 1993
• 052046 - collected by K. R. Wood in 1996
• 033801 - collected by K. R. Wood in 1997
• 030586 - collected by K. R. Wood in 1998
• 028856 - collected by Steve Perlman in 1998
• 025229 - collected by Steve Perlman in 1998
• 025228 - collected by Steve Perlman in 1998
• 028614 - collected by K. R. Wood in 1999
• 057166 - collected by K. R. Wood in 2000
• 030608 - collected by Steve Perlman in 2000
• 051990 - collected by K. R. Wood in 2000
• Unassigned - collected by Steve Perlman in 2001
• 052012 - collected by Natalia Tangalin in 2004
• 044317 - collected by K. R. Wood in 2004
• 055431 - collected by K. R. Wood in 2005
• Unassigned - collected by Natalia Tangalin in 2005
• 054840 - collected by K. R. Wood in 2006
• 047867 - collected by Clay Trauernicht in 2007
• 049377 - collected by Clay Trauernicht in 2008
• 048957 - collected by Clay Trauernicht in 2008
• 049359 - collected by Clay Trauernicht in 2008
• 049366 - collected by Natalia Tangalin in 2008
• 050446 - collected by Steve Perlman in 2009
• 064225 - collected by Steve Perlman in 2009
• 053091 - collected by Natalia Tangalin in 2010
• 059105 - collected by K. R. Wood in 2011
• 059100 - collected by K. R. Wood in 2011
• 059133 - collected by K. R. Wood in 2011
• 059352 - collected by K. R. Wood in 2011
• 062580 - collected by K. R. Wood in 2012
• 063022 - collected by K. R. Wood in 2012
• 065082 - collected by Steve Perlman in 2012
• 068466 - collected by Steve Perlman in 2013
• 082717 - collected by K. R. Wood in 2015
• 082714 - collected by K. R. Wood in 2015
• 085166 - collected by K. R. Wood in 2015
• 085210 - collected by K. R. Wood in 2015
• 076402 - collected by K. R. Wood in 2015
• Unassigned - collected by Natalia Tangalin in 2016
• 077407 - collected by Uma Nagendra in 2018
• 082142 - collected by Uma Nagendra in 2018
• 088104 - collected by Tim Flynn in 2022