Bromeliaceae

Bromeliad

Bromeliads are mostly herbaceous perennials, although a few have a more tree-like habit. Many are more or less succulent or have other adaptations to resist drought. They may be terrestrial or epiphytic, rarely climbing (e.g. Pitcairnia species).[8] Some species of Tillandsia (e.g. Spanish moss, Tillandsia usneoides) are aerophytes, which have very reduced root systems and absorb water directly from the air.[9] Many terrestrial and epiphytic bromeliads have their leaves in the form of vase-shaped rosettes which accumulate water. Individual leaves are not divided and have parallel veins without cross connections. The epidermis of the leaf contains silica. Bromeliad flowers are aggregated into inflorescences of various forms. The flowers have bracts, often brightly coloured, and distinct calyces of three sepals and corollas of three petals. The flowers have nectaries. They are pollinated by insects, birds (often hummingbirds) or bats, or more rarely (in Navia) they are wind-pollinated. Fruits are variable, typically taking the form of a capsule or a berry.[8]

Bromeliads are able to live in an array of environmental conditions due to their many adaptations. Trichomes, in the form of scales or hairs, allow bromeliads to capture water in cloud forests and help to reflect sunlight in desert environments.[10] Bromeliads with leaf vases can capture water and nutrients in the absence of a well-developed root system.[10] Many bromeliads also use crassulacean acid metabolism (CAM) photosynthesis to create sugars. This adaptation allows bromeliads in hot or dry climates to open their stomata at night rather than during the day, which reduces water loss.[11] Both CAM and epiphytism have evolved multiple times within the family, with some taxa reverting to C3 photosynthesis as they radiated into less arid climates.[12]

Bromeliads are among the more recent plant groups to have emerged. They are thought to have originated in the tepuis of the Guiana Shield approximately 100 million years ago. The greatest number of extant basal species are found in the Andean highlands of South America.[13] However, the family did not diverge into its extant subfamilies until 19 million years ago. The long period between the origin and diversification of bromeliads, during which no extant species evolved, suggests that there was much speciation and extinction during that time, which would explain the genetic distance of the Bromeliaceae from other families within the Poales.[14]

Based on molecular phylogenetic studies, the family is divided into eight subfamilies. The relationship among them is shown in the following cladogram.[13]

The most basal genus, Brocchinia (subfamily Brocchinioideae), is endemic to the Guiana Shield, and is placed as the sister group to the remaining genera in the family.[14] The subfamilies Lindmanioideae and Navioideae are endemic to the Guiana Shield as well.[15]

The West African species Pitcairnia feliciana is the only bromeliad not endemic to the Americas, and is thought to have reached Africa via long-distance dispersal about 12 million years ago.[13]

The family Bromeliaceae is currently placed in the order Poales.

• 
  A Bromeliad
• 
  Billbergia pyramidalis
• 
  Billbergia pyramidalis
• 
  Billbergia vittata Brongniart
• 
  Tillandsia usneoides hanging from branches
• 
  A Bromeliad
• 
  The flower of a Billbergia sp.
• 
  Puya alpestris
• 
  Flower close-up
• 
  A bromeliad
• 
  Tillandsia airplants mounted on the bark of a cork oak

Bromeliads growing on telephone lines in Bolivia

Plants in the Bromeliaceae are widely represented in their natural climates across the Americas. One species (Pitcairnia feliciana) can be found in Africa.[29] They can be found at altitudes from sea level to 4,200 meters, from rainforests to deserts. 1,814 species are epiphytes, some are lithophytes, and some are terrestrial. Accordingly, these plants can be found in the Andean highlands, from northern Chile to Colombia, in the Sechura Desert of coastal Peru, in the cloud forests of Central and South America, in southern United States from southern Virginia to Florida to Texas, and in far southern Arizona.

Bromeliads often serve as phytotelmata, accumulating water between their leaves. One study found 175,000 bromeliads per hectare (2.5 acres) in one forest; that many bromeliads can sequester 50,000 liters (more than 13,000 gallons) of water.[30] The aquatic habitat created as a result is host to a diverse array of invertebrates, especially aquatic insect larvae,[31][32] including those of mosquitos.[33] These bromeliad invertebrates benefit their hosts by increasing nitrogen uptake into the plant.[34][35][36] A study of 209 plants from the Yasuní Scientific Reserve in Ecuador identified 11,219 animals, representing more than 350 distinct species,[37] many of which are found only on bromeliads. Examples include some species of ostracods, small salamanders about 2.5 cm (1 in) in length, and tree frogs. Jamaican bromeliads are home to Metopaulias depressus, a reddish-brown crab 2 cm (0.8 in) across, which has evolved social behavior to protect its young from predation by Diceratobasis macrogaster, a species of damselfly whose larvae live in bromeliads. Some bromeliads even form homes for other species of bromeliads.[30]

Trees or branches that have a higher incidence of sunlight tend to have more bromeliads. In contrast, the sectors facing west receive less sunlight and therefore fewer bromeliads. In addition, thicker trees have more bromeliads, possibly because they are older and have greater structural complexity.[38][39]

Bromeliaceae mixed cultivated collection

Humans have been using bromeliads for thousands of years. The Incas, Aztecs, Maya and others used them for food, protection, fiber and ceremony, just as they are still used today. European interest began when Spanish conquistadors returned with pineapple, which became so popular as an exotic food that the image of the pineapple was adapted into European art and sculpture. In 1776, the species Guzmania lingulata was introduced to Europe, causing a sensation among gardeners unfamiliar with such a plant. In 1828, Aechmea fasciata was brought to Europe, followed by Vriesea splendens in 1840. These transplants were so successful, they are still among the most widely grown bromeliad varieties.

In the 19th century, breeders in Belgium, France and the Netherlands started hybridizing plants for wholesale trade. Many exotic varieties were produced until World War I, which halted breeding programs and led to the loss of some species. The plants experienced a resurgence of popularity after World War II. Since then, Dutch, Belgian and North American nurseries have greatly expanded bromeliad production.

Only one bromeliad, the pineapple (Ananas comosus), is a commercially important food crop. Bromelain, a common ingredient in meat tenderizer, is extracted from pineapple stems. Many other bromeliads are popular ornamental plants, grown as both garden and houseplants.

Bromeliads are important food plants for many peoples. For example, the Pima of Mexico occasionally consume flowers of Tillandsia erubescens and T. recurvata due to their high sugar content; in Argentina and Bolivia, the shoot apices of T. rubella and T. maxima are consumed; in Venezuela, indigenous coastal tribes eat a sour-tasting but sweet-smelling berry, known as 'Maya', of Bromelia chrysantha as a fruit or in fermented beverages.[40]

• List of foliage plant diseases (Bromeliaceae)

Wikimedia Commons has media related to Bromeliaceae.

Wikispecies has information related to Bromeliaceae.

• The New Bromeliad Taxon List A constantly updated list of current Bromeliad names and synonyms.
• Luther, H. E. (2008) An Alphabetical List of Bromeliad Binomials, Eleventh Edition The Marie Selby Botanical Gardens, Sarasota, Florida. Published by The Bromeliad Society International.
• Bromeliad care information
• Bromeliad cultivar registry
• Bromeliads of Chile in Chileflora
• Palm trees, small palms, Cycads, Bromeliads and tropical plants Photos of Bromeliads and associated flora, with information on habitat and cultivation.