Clusia

Clusia is the type genus of the flowering plant family Clusiaceae. Comprising 300-400 species, it is native to tropical America. The genus is named by Carl Linnaeus in honor of the botanist Charles de l’Écluse. The closest relatives of Clusia are the neotropical genera Chrysochlamys, Tovomita, Dystovomita and Tovomitopsis. Together with Clusia, these genera form the tribe Clusieae, where the fruit is a fleshy capsule with arillate seeds. The distribution ranges from the Florida Keys and southern Mexico to southernmost Brazil, and from near sea level to at least 3500 m altitude in the northern Andes. Species of Clusia are a characteristic component of a number of Neotropical vegetation types, and may even be dominant, as is often seen in montane forests of the Greater Antilles. Most species are found in lowland or montane rainforests, but some occur in drier habitats such as the restingas of Brazil, caribbean coastal scrub and dry interandean valleys. A number of species are confined to rocky habitats, such as tepuis or granitic inselbergs. A few grow as scattered shrubs in paramo. The apomictic Clusia rosea is naturalized in e.g. Hawaii. Its species are shrubs, vines and small to medium-size trees up to 20 m tall, with evergreen foliage. Some species start life as epiphytes, then develop long roots that descend to the ground and eventually strangle and kill the host tree in a manner similar to strangler figs. Many Clusia species have Crassulacean acid metabolism, which can be considered an adaptation to the often dry (micro)habitats of the genus. The plants contain variously coloured latex in stems, leaves and fruit. The leaves are opposite, 5–20 cm long and 2–10 cm broad, with a leathery texture and an entire margin. Flower size varies from ca 5 mm wide (e.g. Clusia gundlachii) to ca 150 mm in Clusia grandiflora. The 4-9 petals are white, cream, yellow, pink, red, blackish or green. Flowers are unisexual and plants are dioecious (pistillate and staminate flowers are borne on separate plants). Stamen number ranges from four to several hundred. Shape and size of stamens are extremely variable. Sterile stamens are often present, both in pistillate and staminate flowers. Stigmas are four to 16 in number and usually sessile. The fruit is a leathery valvate capsule which splits open to release several red or orange, fleshy-coated seeds. Pollination involves a range of different animals, and several types of rewards. Floral resin occurs in many, probably most species of Clusia. The resin is produced by the stamens (by sterile stamens, referred to as staminodes, in pistillate flowers) and is collected by bees that use it in nest construction. Nectar is most common in montane species, e.g. Clusia clusioides, and these flowers are visited by insects such as moths and wasps, and sometimes by bats or hummingbirds. In flowers lacking nectar or resin, pollination may be carried out by pollen-eating beetles, which visit also the rewardless pistillate flowers, as observed in Clusia criuva. Clusia blattophila is pollinated by male cockroaches attracted by a pheromone-containing fluid produced by the flowers.