Part 2

Introduction—Part 2:

A Brief Review of Flora of the Hawaiian Islands

Key to Species Classifications:

Native—Arrived in the Hawaiian Islands without the aid of humans (indigenous), or evolved in the Hawaiian Islands (endemic).

Indigenous—Native to the Hawaiian Islands and other places.

Endemic—Evolved in the Hawaiian Islands from an indigenous species; native to the Hawaiian Islands and nowhere else.

Polynesian Introduction—Brought to the Hawaiian Islands by the early Polynesian settlers.

Post-Contact Introduction—Brought to the Hawaiian Islands after Western contact (1778).

Naturalized—Not native to the Hawaiian Islands, but now growing wild in the Hawaiian Islands.

Adaptive Radiation and Endangered Species

The evolutionary process of adaptive radiation (or evolutionary divergence) describes how so few colonizing species in to the Hawaiian Islands managed to evolve, over many millennia, into a fascinating array of endemic flora and fauna, including thousands of species found nowhere else on Earth. (See Honeycreepers and Honeyeaters section in Native Birds of the Hawaiian Islands, Chapter 7, for a more in-depth explanation of adaptive radiation.)

The 1999 Manual of the Flowering Plants of Hawai‘i: Revised Edition[i] documented 956 native Hawaiian flowering plants (850 endemic). Since that 1999 publication, at least 32 new Hawaiian species were discovered (as of 2002) and documented in the Electronic Supplement to the Manual of the Flowering Plants of Hawai‘i.[ii]

These and other newly discovered species as well as other classification changes have now further increased the total number of documented native Hawaiian flowering plant species.

Bishop Museum’s Records of the Hawaii Biological Survey for 2000[iii] (published in 2002) documented 1,163 native Hawaiian flowering plants (918 endemic).

This extremely high rate of flowering plant endemism (about 79%) is the highest in the world for a plant region, and is primarily attributed to the extreme isolation of the Hawaiian Islands, along with the diversity of habitats and food sources that have allowed many very different species to evolve.

Isolation alone did not lead to such a high rate of endemism, nor did the quantity of habitats and food sources, but together these factors have created an unmatched multitude of unique species on the land, in the air and in the surrounding ocean, species found nowhere else in the world except the Hawaiian Islands.

Speciation and Endemism—Lobelias and Honeycreepers

During the millions of years after the Hawaiian Islands rose up from the deep sea, relatively few species made it to the Hawaiian Islands. These original colonizers eventually evolved into many new species. New species development (speciation) occurred at different rates for plants, insects, birds and marine life.

Less than 300 original colonizing flowering plant species evolved into the 1,163 documented native Hawaiian flowering plant species. Approximately 29 of the original colonizing plant species evolved into more than half of today’s native Hawaiian flowering plants.

This extremely high speciation rate, like endemism, is typical of extremely isolated locations, and is another fascinating example of the evolutionary process known as adaptive radiation.

Perhaps the most remarkable example of adaptive radiation is provided by the endemic Hawaiian plant species in the Campanulaceae family (the bellflower family), which includes some of the most beautiful flowers in the Hawaiian Islands.

All of these flowers are the result of a single colonizing plant species, one ancestral species that evolved into more than 120 uniquely Hawaiian species, all in the Campanulaceae subfamily Lobelioideae (the lobelias). This conclusion is based on molecular analyses documented in the Electronic Supplement to the Manual of the Flowering Plants of Hawai‘i.[iv]

The amazing story of adaptive radiation, speciation, and endemism in the Hawaiian Islands is also demonstrated in the record of Hawaiian birds. A prominent example: a single species of finch birds evolved into more than 50 unique species and subspecies of Hawaiian honeycreepers.

This single colonizing population of finches took hold in the Hawaiian archipelago about 15 to 30 million years ago, long before the eight main Hawaiian Islands had come into existence. The islands that were prominent then are now all but eroded away into the sea, and are known as the Northwestern Hawaiian Islands and protected within the Papahānaumokuākea Marine National Monument. (See Northwestern Hawaiian Islands, Chapter 2.)

The birds, however, continued to multiply and evolve, island-hopping down the growing chain of volcanoes as new habitat became available. Unfortunately, more than half of the honeycreeper species are now extinct, and most of those that remain are endangered. (See Native Birds of the Hawaiian Islands, Chapter 7.)

The native Hawaiian honeycreepers evolved in concert (co-evolved) with the long tubular flowers of the Lobelioideae species that perfectly fit the long, curving beaks of the birds that pollinated the flower blossoms. Unfortunately, 25% of Lobelioideae are now extinct, as are more than 50% of the honeycreeper bird species that once pollinated the flowers.

The high rate of speciation in the Hawaiian Islands is also exhibited in many other endemic genera, such as ko‘oko‘olau (Bidens species), the 19 endemic Hawaiian daisy species that evolved from a single colonizing species. Many ko‘oko‘olau species are now rare and endangered.

Endangered Species

As of 7/20/2002, there were 317 listings of threatened and endangered species in the Hawaiian Islands. This is documented in the Federal Register, 2002, Vol. 67, U.S. Fish & Wildlife Service[v]

Twenty-seven species that were presumed to be extinct in the 1990 Manual of the Flowering Plants of Hawai‘i were subsequently rediscovered, and documented as such in the 1999 Manual of the Flowering Plants of Hawai‘i: Revised Edition.[vi]

In the 2002 Electronic Supplement to the Manual of the Flowering Plants of Hawai‘i,[vii] at least 32 new species and two new subspecies discoveries are documented, along with one new endemic genus. The Electronic Supplement also lists numerous name (nomenclatural) changes, “resurrections from synonymy,” and corrections of past misidentifications.

Many of these changes have further increased the total number of documented native Hawaiian species and subspecies. In addition, many more species that were presumed extinct were rediscovered (in addition to the 27 rediscoveries between 1990 and 1999).

Detailed botanical analyses will continue to discern subtle differences in plant populations, leading to further refinements in botanical classifications. Continuing field investigations will almost certainly yield more discoveries of new plant species as well as rediscoveries of species currently believed to be extinct.

Meanwhile, hundreds of native Hawaiian species move closer to extinction each year, and the list of extinct Hawaiian species continues to grow. (See Overview of Native and Polynesian-Introduced Species of the Hawaiian Islands, Chapter 5.)

The status of the many endangered species in the Hawaiian Islands will also continue to change as some populations recover and others become extinct. Native species are negatively affected by invasive introduced species, loss of habitat due to agricultural and commercial development, and a host of other problems (see Overview of Chapter 5).

Plant cultivation projects as well as bird propagation efforts aid in the survival of endangered species and help to restore critically low populations. Many community-based efforts also seek to protect native ecosystems and their inhabitants.

Note on Sources—Native Hawaiian and Polynesian-Introduced Plants and Ferns

Plant and fern information in this text comes from a wide variety of sources that are listed at the end of each chapter as well as in Appendix 1: Note On Sources; and Appendix 3: Complete List of Sources.

For plant taxonomy (scientific classifications), this text defers primarily to the 1999 Manual of the Flowering Plants of Hawai‘i: Revised Edition (Wagner, W.L., Herbst, D.R., and Sohmer, S.H.: University of Hawai‘i Press; Bishop Museum Press, 1999) for family, species and genus names as well as subspecies and variety classifications.

Information about plant species mentioned in this text includes botanical classification updates as listed in the 2002 Electronic Supplement to the Manual of the Flowering Plants of Hawai‘i.[viii] For taxonomy of ferns and fern allies, this text defers to the 2002 University of Hawai‘i Botany Department’s Hawaiian Native Plant Genera.[ix]

Information regarding federal endangered species listings relies on the 2002 Federal Register.[x] Species numbers have been updated using the Records for the Hawaii Biological Survey for 2000,[xi] published by the Bishop Museum in 2002.


 

Summary of Botanical Reclassifications

Following is a brief summary of recent changes in botanical classifications regarding endemic, indigenous and naturalized Hawaiian species.

The changes noted here pertain to plants mentioned in this text, and encompass a significant subset of the native and Polynesian-introduced plants important in ancient Hawaiian culture.

The following taxonomical changes (also noted at various points throughout this book) are based on the 2002 Electronic Supplement to the Manual of the Flowering Plants of Hawai‘i,[xii] here referred to as the “Supplement,” which contains the latest updates to the Manual of the Flowering Plants of Hawai‘i: Revised Edition,[xiii] here referred to as the “Manual.”

ü ‘Ahu‘awa (Cyperus javanicus). ‘Ahu‘awa was formerly classified (in the Manual) as Mariscus javanicus. According to the Supplement, the Mariscus genus is no longer recognized, and all Hawaiian species formerly in that genus should instead be placed in the Cyperus genus (thus ‘ahu‘awa is now classified as Cyperus javanicus).

On the 2002 federal endangered species list[xiv] the genus was still listed as Mariscus, with two species listed as endangered (M. fauriei and M. pennatiformis).

ü ‘Ākala (Hawaiian raspberry). Rubus hawaiensis and Rubus macrei (both known by the Hawaiian term ‘ākala) are recognized in the Supplement as being the result of independent colonizations. Formerly (in the Manual), R. macrei was considered a derivative of Rubus hawaiensis.

ü Hau (formerly Hibiscus tiliaceus). Hau was reclassified (by the Supplement) as Talipariti tiliaceum. This reclassification also changes the number of native Hawaiian Hibiscus species from seven to six.

ü Kā‘e‘e (Sea Bean). Kā‘e‘e was formerly classified (in the Manual) as Mucuna gigantea but was changed to Mucuna gigantea subspecies gigantea in the Supplement. Maka hipa (sheep’s-eye), formerly known as Mucuna urens, was changed to Mucuna sloanei.

ü Kohekohe (Spikerush). As documented in the Manual, the Hawaiian term kohekohe (common name: spikerush) refers to the two endemic as well as the two naturalized Hawaiian species in the Eleocharis genus. The Supplement lists two new Eleocharis arrivals (naturalized) in the Hawaiian Islands: E. olivacea and E. schaffneri.

ü Koia‘e (Acacia koiae). Koia‘e (also called koia‘a) was formerly considered (in the Manual) as a variety of koa (Acacia koa), but has been reclassified (by the Supplement) as a separate species, named Acacia koiae.

ü Kōlea (formerly classified as Myrsine emarginata) was reclassified (by the Supplement) within Myrsine lessertiana. Myrsine mezii, thought to be extinct, was rediscovered on Kaua‘i. Endemic species in Myrsine genus now number 19 instead of 20.

ü Kou (Cordia subcordata) has long been considered a Polynesian introduction (as documented in the Manual), but recent subfossil seed discoveries resulted in the reclassification of Cordia subcordata as indigenous (as documented in the Supplement, based on a study published in 2001 in the journal Ecological Monographs.[xv]

ü Lobelias. All species in family Campanulaceae genus Lobelia have been reclassified (by the Supplement) into either the genus Neowimmeria or the genus Galeatella.

Other classification changes as well as new species discoveries in the Campanulaceae family have increased the 53 endemic species formerly recognized in the Manual to 58 endemic Cyrtandra species (as documented in the Supplement).

Recent molecular analyses (documented in the Supplement) also show that all of the more than 120 endemic species in the Campanulaceae subfamily Lobelioideae (the lobelias) evolved from a single colonizing species.

ü Loulu (Pritchardia species). Two new Pritchardia species: P. limahuliensis and P. perlmanii, were not recognized in the Manual, but are recognized in the Supplement. Both species are found on Kaua‘i, and both are extremely rare and endangered.

Another Pritchardia species, P. lanaiensis, is also documented in the Supplement after having previously been considered (in the Manual) doubtful for the species classification.

The three new Pritchardia species documented in the Supplement bring the number of endemic Hawaiian Pritchardia species to 22 (the Manual documented 19 endemic Pritchardia).

Naupaka. A new species of naupaka (Scaevola hobdyi), documented in the Supplement, brings the number of native Scaevola to ten species (nine endemic).



[i] Wagner, Warren L., Herbst, Derral R., and Sohmer, S.H. Manual of the Flowering Plants of Hawai‘i: Revised Edition, Volumes 1 and 2. Honolulu: University of Hawai‘i Press; Bishop Museum Press, 1999.

[ii] Wagner, Warren L., and Herbst, Derral R. Electronic Supplement to the Manual of the Flowering Plants of Hawai‘i. Internet site: http://rathbun.si.edu/botany/pacificislandbiodiversity/hawaiianflora/supplement.htm, 3/05/2002.

[iii] Evenhuis, Neal L., and Eldredge, Lucius G., Editors. Records of the Hawaii Biological Survey for 2000. Bishop Museum Occasional Papers, Number 68, 69. Honolulu: Bishop Museum, 3/25/2002.

[iv] Wagner, Warren L., and Herbst, Derral R. Electronic Supplement to the Manual of the Flowering Plants of Hawai‘i. Internet site: http://rathbun.si.edu/botany/pacificislandbiodiversity/hawaiianflora/supplement.htm, 3/05/2002.

[v] Federal Register, 2002, Vol. 67, U.S. Fish & Wildlife Service, Threatened and Endangered Species System (TESS), Listings by State and Territory as of 7/20/2002. Internet site: http://ecos.fws.gov/servlet/TESSWebpageUsaLists?state=HI, 7/28/2002.

[vi] Wagner, Warren L., Herbst, Derral R., and Sohmer, S.H. Manual of the Flowering Plants of Hawai‘i: Revised Edition, Volumes 1 and 2. Honolulu: University of Hawai‘i Press; Bishop Museum Press, 1999.

[vii] Wagner, Warren L., and Herbst, Derral R. Electronic Supplement to the Manual of the Flowering Plants of Hawai‘i. Internet site: http://rathbun.si.edu/botany/pacificislandbiodiversity/hawaiianflora/supplement.htm, 3/05/2002.

[viii] Wagner, Warren L., and Herbst, Derral R. Electronic Supplement to the Manual of the Flowering Plants of Hawai‘i. Internet site: http://rathbun.si.edu/botany/pacificislandbiodiversity/hawaiianflora/supplement.htm, 3/05/2002.

[ix] Hawaiian Native Plant Genera. University of Hawai‘i Botany Department. Internet site: http://www.botany.hawaii.edu/faculty/carr/natives.htm, 5/03/2002.

[x] Federal Register, 2002, Vol. 67, U.S. Fish & Wildlife Service, Threatened and Endangered Species System (TESS), Listings by State and Territory as of 7/20/2002. Internet site: http://ecos.fws.gov/servlet/TESSWebpageUsaLists?state=HI, 7/28/2002.

[xi] Evenhuis, Neal L., and Eldredge, Lucius G., Editors. Records of the Hawaii Biological Survey for 2000. Bishop Museum Occasional Papers, Number 68, 69. Honolulu: Bishop Museum, 3/25/2002.

[xii] Wagner, Warren L., and Herbst, Derral R. Electronic Supplement to the Manual of the Flowering Plants of Hawai‘i. Internet site: http://rathbun.si.edu/botany/pacificislandbiodiversity/hawaiianflora/supplement.htm, 3/05/2002.

[xiii] Wagner, Warren L., Herbst, Derral R., and Sohmer, S.H. Manual of the Flowering Plants of Hawai‘i: Revised Edition, Volumes 1 and 2. Honolulu: University of Hawai‘i Press; Bishop Museum Press, 1999.

[xiv] Federal Register, 2002, Vol. 67, U.S. Fish & Wildlife Service, Threatened and Endangered Species System (TESS), Listings by State and Territory as of 7/20/2002. Internet site: http://ecos.fws.gov/servlet/TESSWebpageUsaLists?state=HI, 7/28/2002.

[xv] Burney, David A., James, Helen F., Burney, Lida Pigott, Olson, Storrs L., Kikuchi, William, Wagner, Warren L., Burney, Mara, McCloskey, Deirdre, Kikuchi, Delores, Grady, Frederick V., Gage II, Reginald, and Nishek, Robert. Fossil evidence for a diverse biota from Kaua‘i and its transformation since human arrival. Ecological Monographs, 71 (4), 2001, pp. 615-641.