Bottle palm  (Hyophorbe lagenicaulis)

The bottle palm is classified as Critically Endangered (CR D) on the IUCN Red List 2004 (1).

The swollen, smooth, grey trunk of this palm species is bulbous at the bottom, resembling a bottle when young. As the tree matures, the width of the trunk evens out, appearing slightly conical in the oldest individuals. Emerging from the top of the trunk are between four and eight long fronds (leaves). Each frond arches upwards and curves down splendidly. The fronds are feather-like with leaflets splaying out from each side of a central midrib (leaf vein). Numerous white flowers grow on stalks at the crown of the tree, and following the flowering, small, round fruits appear, changing from green to black as they age (2).

Endemic to Round Island; part of the Mascarene Island group in the Indian Ocean, 20 km off the northern coast of Mauritius (2).

Found amongst lowland palm savanna (1).

From the Greek for ‘pig’ and ‘food’, Hyophorbe species are so called as their fruits are said to be eaten by pigs. The specific name lagenicaulis means ‘bottle stalk’ in Latin. The bottle palm is a monoecious plant, bearing both sexes on each plant. As the female flowers die, they are followed by fleshy fruits (2).

The palm savannah habitat still found on Round Island was once characteristic of the northern plain of Mauritius, but this is now lost to development. As one of the few islands still free from introduced rats, Round Island has a high conservation value. It supports many breeding seabirds as well as eight species of native reptile. It suffered following the introduction of goats and rabbits in the 19th century, as their zealous over-grazing caused extreme soil erosion. In the 1970s the goats were successfully eradicated, but the rabbits were more difficult to remove. As the destruction caused by the rabbits continued to increase into the 1980s, Jersey Wildlife Preservation Trust funded three scientists who were challenged to exterminate the rabbits on Round Island. In just two months, these scientists were able to poison every rabbit on the island, and a year later in 1987 it was declared rabbit-free. Invasive weeds were also removed, and native vegetation was found to be growing prolifically (3).

As one of the most successful and exemplary cases of conservation in the world, Round Island is a managed reserve and is now preparing for the introduction of carefully chosen critically endangered animals and plants from Mauritius (3). Regeneration of the bottle palm will benefit immeasurably from the removal of goats and rabbits (1).

For further information on Round Island see:

• 
  http://www.mauritiusencyclopedia.com/Nature/Geography/Islets/RoundIsland/Success.htm
• 
  http://www.mauritian-wildlife.org/article.php?cat=projects&title=05.%20Round%20Island