The Bromeliaceae (the bromeliads) are a family of monocot of about 80 genera and 3700 known species, native mainly to the Tropics Americas, with several species found in the American subtropics and one in tropical west Africa, Pitcairnia feliciana.
It is among the basal families within the Poales and is the only family within the order that has Septal nectary and inferior ovaries.Judd, Walter S. Plant systematics a phylogenetic approach. 3rd ed. Sunderland, MA: Sinauer Associates, Inc., 2007. These inferior ovaries characterize the Bromelioideae, a subfamily of the Bromeliaceae. The family includes both , such as Spanish moss ( Tillandsia usneoides), and terrestrial species, such as the pineapple ( Ananas comosus). Many bromeliads are able to store water in a structure formed by their tightly overlapping leaf bases. However, the family is diverse enough to include the tank bromeliads, grey-leaved epiphytic Tillandsia species that gather water only from leaf structures called , and many desert-dwelling .
The largest bromeliad is Puya raimondii, which reaches tall in vegetative growth with a flower spike tall, and the smallest is Spanish moss.
Bromeliads are able to live in an array of environmental conditions due to their many adaptations. , in the form of scales or hairs, allow bromeliads to capture water in cloud forests and help to reflect sunlight in desert environments. Bromeliads with leaf vases can capture water and nutrients in the absence of a well-developed root system. Many bromeliads also use crassulacean acid metabolism (CAM) photosynthesis to create sugars. This adaptation allows bromeliads in hot or dry climates to open their at night rather than during the day, which reduces water loss. 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.
Based on molecular phylogenetic studies, the family is divided into eight subfamilies. The relationship among them is shown in the following cladogram.
The most basal genus, Brocchinia (subfamily Brocchinioideae), is endemic to the Guiana Shield, and is placed as the Cladistics to the remaining Genus in the family. The subfamilies Lindmanioideae and Navioideae are endemic to the Guiana Shield as well.
The species Pitcairnia feliciana is the only bromeliad not Endemism to the Americas, and is thought to have reached Africa via long-distance dispersal about 12 million years ago.
Even before this, a few other bromelioids had already dispersed to the Brazilian shield while the climate was still arid, likely through a gradual process of short-distance dispersal. These make up the terrestrial members of the Bromelioideae, which have highly xeromorphic characters.
Bromeliaceae were originally split into three subfamilies based on morphological seed characters: Bromelioideae (seeds in Berry fruits), Tillandsioideae (plumose seeds), and Pitcairnioideae (seeds with wing-like appendages). However, molecular evidence has revealed that while Bromelioideae and Tillandsioideae are monophyletic, Pitcairnioideae as traditionally defined is Paraphyly and should be split into six subfamilies: Brocchinioideae, Lindmanioideae, Hechtioideae, Navioideae, Pitcairnioideae, and Puyoideae.
Brocchinioideae is defined as the most basal branch of Bromeliaceae based on both morphological and molecular evidence, namely genes in chloroplast DNA.
Lindmanioideae is the next most basal branch distinguished from the other subfamilies by convolute sepals and chloroplast DNA.
Hechtioideae is also defined based on analyses of chloroplast DNA; similar morphological adaptations to arid environments also found in other groups (namely the genus Puya) are attributed to convergent evolution.
Navioideae is split from Pitcairnioideae based on its cochlear sepals and chloroplast DNA.
Puyoideae has been re-classified multiple times and its monophyly remains controversial according to analyses of chloroplast DNA.
==Gallery==
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.Gename, K., & Monge-Nájera, J. (2012). How organisms reach and colonize bromeliads: a field experimental test of two of Picado’s hypotheses, and the effect of tree age and cardinal distribution on bromeliads in Cartago, Costa Rica. UNED Research Journal, 4(2), 181-186.López, L. C. S., Alves, R. R. D. N., & Ríos, R. I. (2009). Micro-environmental factors and the endemism of bromeliad aquatic fauna. Hydrobiología, 625(1), 151-156.
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, Netherlands, Belgium 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 , grown as both garden and .
Bromeliads are important food plants for many peoples. For example, the Pima people 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; in Chile, the sweet fruit of Greigia sphacelata, known as 'chupones', is consumed raw.
Radiation of Tillandsioideae and Hechtia
Evolution of the Bromelioideae
Classification
Subfamilies
Genera
Hybrid genera
Distribution and habitat
Ecology
Cultivation and uses
Collectors
See also
External links
|
|