Coco de mer

                                     

Lodoicea, commonly known as the sea coconut, coco de mer, or double coconut, is a monotypic genus in the palm family. The sole species, Lodoicea maldivica, is endemic to the islands of Praslin and Curieuse in the Seychelles. It formerly also was found on the small islets of St Pierre, Chauve-Souris and Ile Ronde (Round Island), all located near Praslin, but has become extinct there. The name of the genus, Lodoicea, is derived from Lodoicus, the Latinised form of Louis, in honour of King Louis XV of France.

Description
The tree grows to 25–34 m tall. The leaves are fan-shaped, 7–10 m long and 4.5 m wide with a 4 m petiole. It is dioecious, with separate male and female plants. The male flowers are catkin-like, up to 1 m long. The mature fruit is 40–50 cm in diameter and weighs 15–30 kg, and contains the largest seed in the plant kingdom. The fruit, which requires 6–7 years to mature and a further two years to germinate, is sometimes also referred to as the sea coconut, love nut, double coconut, coco fesse, or Seychelles nut.

While the functional characteristics of Lodoicea are similar to other trees of monodominant forests in the humid tropics, its unique features include a huge seed, effective funnelling mechanism and diverse community of closely associated animals. These attributes suggest a long evolutionary history under relatively stable conditions. Of the six monospecific endemic palms in Seychelles, Lodoicea is the "only true case of island gigantism among Seychelles flowering plants, a unique feature of Seychelles vegetation" (Proctor, 1984). It holds three botanical records: the largest fruit so far recorded weighed 42 kg, the mature seeds weighing up to 17.6 kg are the world's heaviest, and the female flowers are the largest of any palm.

Of the six endemic palms it is the only dioecious species, with male and female flowers located on different plants.

Habit
Lodoicea is robust, solitary, up to 30 m tall with an erect, spineless, stem which is ringed with leaf scars (Calstrom, unpublished). The base of the trunk is of a bulbous form and this bulb fits into a natural bowl, or socket, about 2.5 ft in diameter and 18 inches in depth, narrowing towards the bottom. This bowl is pierced with hundreds of small oval holes about the size of a thimble with hollow tubes corresponding on the outside through which the roots penetrate the ground on all sides, never, however, becoming attached to the bowl; they are partially elastic, affording an almost imperceptible but very necessary "play" to the parent stem when struggling against the force of violent gales.

Leaves
The crown is a rather dense head of foliage with leaves that are stiff, palmate up to 10 m in diameter and petioles of two to four metres in length. The leaf is plicate at the base, cut one third or more into segments 4–10 cm broad with bifid end which are often drooping. A triangular cleft develops at the petiole base.The palm leaves form a huge funnel that intercepts particulate material, especially pollen, which is flushed to the base of the trunk when it rains. In this way, Lodoicea improves its nutrient supply and that of its dispersal-limited offspring.

Flowers
The clusters of staminate flowers are arranged spirally and are flanked by very tough leathery bracts. Each has a small bracteole, three sepals forming a cylindrical tube, and a three-lobed corolla. There are 17 to 22 stamens. The pistillate flowers are solitary and borne at the angles of the rachis and are partially sunken in it in the form of a cup. They are ovoid with three petals as well as three sepals. It has been suggested that they may be pollinated by animals such as the endemic lizards which inhabit the forest where they occur. Pollination by wind and rain are also thought to be important. Only when Lodoicea begins to produce flowers, which can vary from 11 years to 45 or more, is it possible to determine the sex of the plan

Fruit
The fruit is bilobed, flattened, 40 to 50 cm long ovoid and pointed, and contains usually one but occasionally two to four seeds. The epicarp is smooth and the mesocarp is fibrous. The endosperm is thick, relatively hard, hollow and homogenous. The embryo sits in the sinus between the two lobes. During germination a tubular cotyledonary petiole develops that connects the young plant to the seed. The length of the tube is reported to reach about four metres.In the Vallee de Mai the tube may be up to 10 m long.