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Amborella

Scientific name: Amborella trichopoda

Until recently, Amborella trichopoda was a little known plant native to the rainforests of New Caledonia, a small island in the South Pacific. Amborella gained fame after DNA evidence consistently indicated that it is “sister” to all other living flowering plants (Qiu et al., 2000, 2005; Soltis et al., 1999, 2000, 2002; Parkinson et al., 1999; Mathews and Donoghue, 1999; Zanis et al., 2005).   This means that Amborella trichopoda is a descendent of the oldest confirmed branch in the flowering plant family tree.  It is notable that is also the sole extant (living) species in its line of ancestry.

Amborella trichopoda is a small, evergreen, shrub that occurs only in the moist, shaded understory of tropical mountainside forests of New Caledonia. Plants are unisexual, meaning they will either produce all male or all female flowers; thus, cross-pollination between plants is required for reproduction. Female flowers are both wind and insect pollinated (Thien et al., 2003)

Amborella flowers are tiny, typically about 4-8 mm.  The petals and sepals are indistinguishable, so botanists call them tepals. Additionally, there are a variable number tepals (typically around 3-8).  A Male flower has anywhere from 6 to 100 flat, reflexed stamens, the male reproductive organs; female flowers bear 3-8 carpels, the female reproduction organs (Thien et al., 2000; Watson and Dallwitz, 2005).   If pollinated, female Amborella flowers develop into small red berries, each containing a single seed (See photo).

Author: Heather Fara, University of Florida. Send comments or corrections

 

Native to New Caledonia

Map: Red dot indicates the location of New Caledonia, a small island in the South Pacific. This is the only place in the world that Amborella is found natively. Map created by Heather Fara, University of Florida.

femalemale flowerfruit

Photos: (a) Female flowers, taken by Sangtae Kim, University of Florida. (b) Male flowers, taken by Bill Laidlaw, National Tropical Botanical Gardens. (c) Mature fruit, taken byJean-Marie Veillon, Faune et Flore de Nouvelle Calédonie

References:

Mathews & Donoghue (1999) The root of angiosperm phylogeny inferred from duplicate phytochrome genes. Science 286(5441): 947 - 950.

Parkinson, et al. (1999) Multigene analyses identify the three earliest lineages of extant flowering plants. Current Biology 9:1485–1488.

Qiu, et al. (2000) Phylogeny of basal angiosperms: analyses of five genes from three genomes. International Journal of Plant Sciences,161: S3–S27.

Qiu, et al. (2005) Phylogenetic analysis of basal angiosperms based on nine plastids, mitochondrial, and nuclear genes. International Journal of Plant Sciences, 166 (5): 815-842.

Soltis, et. al. (1999) Angiosperm phylogeny inferred from multiple genes as a tool for comparative biology. Nature 402:402–404.

Soltis, et al. (2000) Angiosperm phylogeny inferred from 18S rDNA, rbcL, and atpB sequences. Botanical Journal of the Linnean Society. 133:381–461.

Soltis, et al. (2002) Phylogeny of seed plants based on evidence from 8 genes. American Journal of Botany 89: 1670-1681.

Thien, et al. (2000) New Perspectives on the Pollination Biology of Basal Angiosperms. International Journal of Plant Sciences, 161(S6):S225-S235.

Thien, et al. (2003) The population structure structure and floral biology of amborella trichopoda (amborelleae). Annals of the Missouri Botanical Garden, 90 (3): 466–490.

Watson & Dallwitz (1992 onwards). The families of flowering plants: descriptions, illustrations, identification, and information retrieval. October 12, 2005.

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