Galapagos guava (Psidium galapageium)
|Also known as:||Guayabillo|
|Size||Height: up to 8 m (2)|
This species has not yet been classified by the IUCN.
There are two Psidium species in the Galapagos, but whereas the well-known cultivated guava (P. guajava) is introduced and highly invasive, the Galapagos guava is native to the archipelago and found nowhere else on earth. The Galapagos guava grows as a shrub or a small tree and has simple, elliptic to egg-shaped leaves, and relatively small white flowers. The fruit is a roundish berry that begins yellow but turns reddish brown to black when ripe (2) (3). There are two varieties of the Galapagos guava, with the slightly larger P. g. galapageium being more common than P. g. howellii (2) (3) (4).
Endemic to the Galapagos Islands where it occurs on the islands of San Cristóbal, Santa Cruz, Pinta, Santiago, Fernandina and Isabela (2).
Found in the arid lowlands and moist uplands, where it is a common component of the Scalesia zone, a humid evergreen forest habitat dominated by daisy trees (Scalesia spp.) (2) (3) (4).
Little is known about the biology of the Galapagos guava, but as was noted by Charles Darwin during the voyage of the Beagle, the fruit are a favourite of the archipelago’s giant tortoises (5) (6).
Although the status of Galapagos guava has not yet been assessed by the IUCN, like much of the Galapagos flora, it is probably affected by habitat loss, invasive alien plants such as its congener, P. guajava, and introduced herbivores such as feral goats and donkeys (2) (7).
There are no specific conservation measures in place for the Galapagos guava, but botanical research carried out by the Charles Darwin research station is focused on the conservation of the Galapagos’ native and endemic flora (7). As introduced species pose the greatest risk to the archipelago’s terrestrial biodiversity, actions are already being taken to eradicate the most invasive and destructive animals and plants (7) (8).
For further information on the conservation of the endemic flora of the Galapagos see:
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- Congener: species belonging to the same genus.
- Endemic: a species or taxonomic group that is only found in one particular country or geographic area.
- Varieties: in taxonomy, the science of classifying organisms, varieties are the rank below subspecies. Members of a variety differ from others of the same species in relatively minor ways.
IUCN Red List (June, 2009)
- McMullen, C.K. (1999) Flowering Plants of the Galapagos. Cornell University Press, New York.
- Wiggins, I.L. and Porter, D.M. (1971) Flora of the Galapagos Islands. Stanford University Press, Stanford.
- Porter, D.M. (1968) Psidium (Myrtaceae) in the Galapagos Islands. Annals of the Missouri Botanical Garden, 55(3): 368 - 371.
- Jackson, M.H. (1993) Galapagos: a natural history. University of Calgary Press, Calgary.
- Porter, D.M. (1987) Darwin's notes on Beagle plants. Bulletin of the British Museum (Natural History) Historical Series, 14(2): 145 - 233.
Charles Darwin Foundation (June, 2009)
- Guo, J. (2006) The Galapagos islands kiss their goat problem goodbye. Science, 313: 1567 - .