The Fiji Islands have long been of interest to biogeographers, biologists, and geologists (Raven and Axelrod 1974, Rodda and Kroenke 1984, Thorne 1986). Three of the largest islands (Viti Levu, Vanua Levu, and Taveuni) support harmonic "continental" floras, including many endemic flowering plant species.

Endemic tree species of Fiji include several kinds of primitive conifers including Agathis vitiensis, Acmopyle sahniana, Dacrycarpus imbricatus, Dacrydium nausoriense, Dacrydium nidulum, and Decussocarpus vitiensis. A common gnetophyte (Gnetum gnemon) and a narrowly distributed cycad (Cycas rumphii) occur in the archipelago. Tropical forests of the larger islands yield ten genera of monocotyledonous palms including the monotypic Alsmithia longipes, and the enigmatic dicot flowering plant family, Degeneriaceae. All total in this rich flora of some 6,000 species there are 812 endemic angiospermous and gymnospermous species, 12 endemic genera, and one endemic flowering plant family to the archipelago (A. C. Smith 1996, Table 1).

Some three-hundred other islands of the archipelago are either composed of uplifted interbedded limestones or coral atolls, and exhibit disharmonic (waif) floras (A. C. Smith 1981).

The family Degeneriaceae was discovered in 1942 by I. W. Bailey and A. C. Smith. Professor Smith published additional details of their remarkable discovery in 1949. Degeneriaceae combine a number of primitive features (plesiomorphic traits) that have ignited many debates (A. C. Smith 1981).

Consisting of a single genus and two species Degeneriaceae are endemic to three of the seven "high" islands of the Fiji archipelago (A. C. Smith 1991).

On the left is a picture of a flower of Degeneria roseiflora, and several fragrant flower buds at different stages of maturity. Two of the largest flower buds shown on this kodachrome opened one-by-one on the next two successive nights, releasing a rose-like fragrance (photographed by the author).

Flowering material of Degeneria vitiensis is shown to the right (photographed by Paddy Ryan, Ph.D.). Fragrance of this species resembles Cananga odorata according to Professor Smith (A. C. Smith 1981).

Degenerias combine several archetypic morphological traits including polycotyledony, carpels with evaginating stigmatic plugs (hairs are absent), microsporophylls and not stamens, and monosulcate pollen. Degeneriaceae are close relatives of the Magnoliaceae and Winteraceae (Dahl and Rowley 1962, A. C. Smith 1981, 1991; Carlquist 1989, Harvey 1984). Despite the presence of ancestral (plesiomorphic) traits of female and male organs and vegetative nodal anatomy, Degeneriaceae are not a part of the basal ANITA clade.

Possible hybrid trees were infrequently observed in mixed stands at Mount Delaikoro and on the Natewa Peninsula of Vanua Levu Island. These trees combined some of the floral traits of both species. Staminodes of possibly hybrid flowers were yellow with pink stripes surrounded by an inner ring of magenta microsporophylls. The slide on the left is a flower from the canopy of a possible hybrid tree. The author placed cut branches side-by-side from two different trees of the Delaikoro stand and photographed them (see right image). The pink-flowered trees were prevalent at Mount Delaikoro, however some individual, possibly hybrid trees had larger flowers.

Detailed, but preliminary field studies of degenerias on Vanua Levu Island at Mount Deliakoro (941 meters), highest point in the Korotini Range ("Deliakoro Study Site"), and tree stands near Mount Naitaradamu (1,153 meters) on Viti Levu Island ("Naitaradamu Study Site"), reveal the extent of seed predation by endemic fruit doves and parrots. The fruits of Degeneria vitiensis at Naitaradamu open in a "butterfly" fashion exposing several bright orange or red seeds that dangle from the fruit casing by funiculi (left-hand image).

The high islands of Fiji are Gau (Mount Delaitho, 738 meters), Kadavu (Mount Buke Levu, 838 meters), Koro, Ovalau (Mount Delaiovalau, 626 meters), Taveuni (Mount Uluingalau, 1,241 meters), Vanua Levu (Mount Manuka, elevation 1,194 meters), and Viti Levu (Mount Tomanivi, elevation 1,323 meters).

Vanua Levu Island is "frying-pan-shaped" more than 200 km in length. It includes low mountains such as Mount Mariko (elevation 881 m), visible in the Valaga Range to the far left. The first picture below is a view from the forested slopes of the central spine of Vanua Levu Island near the head of the Yanawai River. The Natewa Peninsula is to the right of the image in the background. The waterbody in the distance is Savu Savu Bay.

The "high" island of Taveuni shown below, located southeast of the "panhandle" of Vanua Levu, is characterized by a summit volcanic crater and several dormant cinder cones and vents (Rodda and Kroenke 1984). The image below was photographed by the late John R. H. Gibbons, Ph.D. from the summit crater rim.

The Degeneria Image Gallery page contains several scanning electron micrographs of the floral organs of Degeneria vitiensis. The scanning electron micrographs are from flower parts collected in tree canopies of Degeneria at the Naitaradamu and Delaikoro study areas.

Flowering and fruiting trees found on a ridge leading to the summit of Mount Naitaradamu, Viti Levu, Fiji (a tree canopy is illustrated to the left), yielded the samples collected and studied by electron microscopy.

On the Rairaimatuku (Nadrau) Plateau of Viti Levu Island, on the slopes of Mount Naitaradamu, and at Monasavu Reservoir, trees of Degeneria vitiensis (known to foresters as "masiratu") were up to 35 meters tall (and one meter in diameter). Trees were generally scattered in patchy stands. Stands of masiratu were several hundred meters apart on highland volcanic plateaus, ravines, and ridges; or on lowland alluvial terraces (for example, along the Rewa River and tributaries). Masiratu trees had distinct, light-green canopies of shiny Magnolia-like foliage borne on terminal, leafy branchlets.

A Nitidulid Beetle Phytophagous Association with Degeneria vitiensis:

Australasian cucujiform nitidulid beetles are pollen- and staminode exudate-feeding residents of the flowers of Degeneria vitiensis. Haptoncus tahktajanii (Nitidulidae, Coleoptera) was described in 1973 by Medvedev, G. S. and M. Ter-Minasyan. The species is a known nectar and pollen feeder (Britton 1970).

Nitidulid beetles feed on the pollen and exudate of Degeneria vitiensis. Staphylinid beetles inhabit the flowers of Degeneria roseiflora while nitidulids are uncommon. The reader may wish to note that the oldest verifiable fossil nitidulid is from Upper Cretaceous Siberian amber, 80 million year's old (Zherikhin and Sukatsheva 1973). Coupled with possible genetic isolation, the rose-flowered species host might have evolved without Australasian nitidulid beetles (Haptoncus tahktajanii).

To the right is a kodachrome of a portion of a flower of Degeneria vitiensis sampled at night from the canopy of a tree located at Mount Naitaradamu, Viti Levu, Fiji. The flower shown to the right is in the female phase. Flowers of degenerias exhibit nyctinastic, circadian movements.

When the flower first opens in the evening a spongy stigmatic plug of a single, conduplicately-folded central carpel is exposed. The carpel is barely visible at the lower left behind the yellow-colored staminodes.

Staminodes of Degeneria vitiensis are covered with bright-yellow, oily exudate. Note the camouflaged nitidulid beetle, Haptoncus tahktajanii feeding on the exudate in the center of the image to the right. A brown microsporophyll is partially hidden between the staminode and the petal to the upper right near the base of two of the many, spirally-arranged petals.

To the left is part of a flower of Degeneria roseiflora from the canopy of a tree located at Mount Delaikoro on Vanua Levu Island. This is the male phase showing purple staminodes with no visible exudate. An outer ring of magenta microsporophylls, and the edge of one petal is visible. Staphylinid beetles were found in this flower. Nitidulids were not observed in these samples.

Scanning electron micrographs of Haptoncus tahktajanii are available in the Haptoncus Image Gallery. Pictures of the dorsal surface of the head and mandibles reveal pollen of Degeneria vitiensis. The images are from a collection of nitidulids found in male and female-phase flowers of Degeneria vitiensis, Naitaradamu study area, Viti Levu, Fiji.

An enlargement of one insect specimen from the gallery of scanning electron micrographs of Haptoncus tahktajanii is shown below. The image is the anterior end of a beetle that was scanned without intermediate fixation or preparatory washes. Two partially crushed boat-shaped monosulcate pollen grains of Degeneria vitiensis are visible in the insect's feeding apparatus. Possible dried staminode exudate covers the front of the head of the beetle.

Conclusions:

Potentially interesting floral variation is seen in stands of Degeneria roseiflora on the island of Vanua Levu, Fiji. Mixed, potentially variable stands of Degeneria roseiflora on Mount Delaikoro are dominated by trees having pink and magenta flowers (with rare individuals possessing larger flowers resembling Degeneria vitiensis).

The Australasian cucujiform nitidulid beetle, Haptoncus tahktajanii (Nitidulidae, Coleoptera), is a pollen- and staminode exudate-feeding resident of the flowers of Degeneria vitiensis. The nitidulids' contribution to the reproductive ecology of Degeneria vitiensis may be trivial. Haptoncus tahktajanii was not present on the flowers of Degeneria roseiflora studied.

Based on the author's studies of more than 200 trees in several native stands on Vanua Levu Island and Viti Levu Island (Miller 1988, 1989), there is much more to be learned of the ecology and population genetics of degenerias.

Literature Cited:

Bailey, I. W. and A. C. Smith. 1942. Degeneriaceae, a new family of flowering plants from Fiji. Journal of the Arnold Arboretum 30: 64-70.

Britton, E. B. 1970. Coleoptera. Page 495-621 In: E. B. Britton (ed.), The Insects of Australia. Melbourne: Melbourne University Press.

Carlquist, S. 1989. Wood and bark anatomy of Degeneria. Aliso 12(3): 485-495.

Dahl, A. O. and J. E. Rowley. 1965. Pollen of Degeneria vitiensis. Journal of the Arnold Arboretum 46: 303-343.

Harvey, W. 1985. Notes on the epidermal features of Degeneria vitiensis (Degeneriaceae). Botanical Journal of the Linnaean Society 90: 201-208.

Medvedev, G. S. and M. Ter-Minasyan. 1973. A new species of beetle of the genus Haptoncus (Coleoptera, Nitidulidae) from the Fiji Islands. Entomologiceskoe Obozrenie 52: 151-153.

Miller, J. M. 1988. A new species of Degeneria (Degeneriaceae) from Fiji Archipelago. Journal of the Arnold Arboretum 69: 275-280.

Miller, J. M. 1989. The archaic flowering plant family Degeneriaceae: its bearing on an old enigma. National Geographic Research 5(2): 218-231.

Raven, P. H. and D. I. Axelrod. 1974. Angiosperm biogeography and past continental movements. Annals of the Missouri Botanical Garden 61: 539-673.

Rodda, P. and L. W. Kroenke. 1984. Fiji: A Fragment Arc. Pp. 87-107 In: Cenozoic Tectonic Development of the Southwest Pacific. United Nations ESCAP, CCOP/SOPAC Technical Bulletin No. 6.

Smith, A. C. 1949. Additional notes on Degeneria vitiensis. Journal of the Arnold Arboretum 30: 1-9.

Smith, A. C. 1981. Degeneriaceae Pp. 7-13 In: Flora Vitiensis Nova, Volume 5. Lawai: Pacific Tropical Botanical Garden.

Smith, A. C. 1991. Addenda et Corrigenda Pp. 577-594 In: Flora Vitiensis Nova, Volume 5. Lawai: National Tropical Botanical Garden.

Smith, A. C. 1996. Comprehensive Indices, Flora Vitiensis Nova, Volume 6. Lawai: National Tropical Botanical Garden.

Thorne, R. F. 1986. Antarctic elements in Australasian rainforests. Telopea 2(6): 611-617.

Zherikhin, V. V. and I. D. Sukatsheva. 1973. One the Cretaceous insect-bearing "ambers" (retinites) from north Siberia. Pp. 3-48, In: E. P. Narchuk (ed.), Problems in Insect Paleontology. Leningrad (St. Petersburg): Nauka.

Acknowledgments:

Field work on Degeneriaceae of the Fiji Islands was sponsored by a grant from the National Geographic Society.

---

[ Contributed Articles: Instructions for Authors ]

Please consider submitting longer articles and notes, educational or popular in content, written in English. Scientific articles should be submitted to an international, peer-reviewed journal, not to the "gigantopteroid" web site. This web site is for educational purposes and not intended to compete with scientific journals.

Written material should be word processed and mailed to us on official letterhead. Illustrations should be sent as separate emailed "jpeg" attachments. Please use PHOTOSHOP or a similar program to create credits in English clearly stating the source of images and graphics. Names of serials to be spelled-out in full will follow Botanico-Periodicum-Huntianum and its supplement. Kindly do not submit articles and/or illustrations that have already been published. The electronic files, submitted in this way, will be peer reviewed by another scientist.  Authors will have the opportunity to revise their manuscripts, based upon peer reviewer's emailed comments, prior to publishing on the "gigantopteroid" web site. I reserve the right to edit and/or delete text not in practice with established English grammar, scientific literary style, and the Botanical Society of America's Statement on Evolution.

Revised, peer-reviewed, and edited text will be converted into "html" format together with images to be cached in a separate folder. Scientific contributions both popular and educational in content, once reviewed and revised, would appear in the following section for an indefinite period of time dependent upon factors beyond our control such as space availability on the hosting server; or upon the backlog of articles submitted for electronic publication.  Older articles may be archived in another electronic format such as "pdf," or placed on another web site registered under the "gigantopteroid"  banner. Our sample style sheet below may be used by converting the html text in MS WORD or equivalent; or by using the "View" and "Page Source" commands when browsing; cut and paste, and create your own template. Alternatively prospective contributors may consult the article above as a guide.

[ Sample Primary Header ]
NAME
ACADEMIC OR OTHER ADDRESS

Secondary Header:

Text space. Please follow these links to examples of a table format and sample image layouts.

Tertiary header.  Text space.

Quaternary header.  Text space.

Sample Literature Cited:

Mamay, S. H. 1976. Paleozoic Origin of the Cycads. U. S. Geological Survey Professional Paper 934.

Meeuse, B. J. D. 1978. The Physiology of Some Sapromyophilous Flowers. Pp. 97-104 In: A. J. Richards, ed., The Pollination of Flowers by Insects. Academic Press: Linnean Society of London.

Niklas, K. J. 1992. Plant biomechanics: An Engineering Approach to Plant Form and Function. Chicago: University of Chicago Press (add number of pages).

Niklas, K. J. 1997. Adaptive walks through fitness landscapes for early vascular plants. American Journal of Botany 84(1) 16-25.

[ top ]