Members of the plant family Bromeliaceae are commonly known as 'bromeliads'. The family contains about 2,700 species and members are characterised by a condensed stem formed by a tight rosette of overlapping leaves. Bromeliads are restricted in distribution to the Neotropics except for one species endemic to West Africa (Pitcairnia feliciana).

'Tank bromeliads' possess modified rosettes that collect rainwater and organic debris. Many tank bromeliads are epiphytes, which means that they grow on other plants without parasitising them. Tank bromeliads are able to live this way because the tank provides them with an alternative source of water and nutrients than the ground soil. Light can be a major limiting factor for plants on the forest floor and the epiphytic lifestyle offers the advantage of access to higher light concentrations without costly investment in large trunks and roots as used by trees.

Main features of a tank bromeliad

Inflorescence: The flowers of a bromeliad are grouped into an inflorescence. This usually appears 4-6 years after germination and occupies a terminal position on the rosette. Bromeliad flowers tend to be short-lived, but most species possess colourful modified leaves called 'floral bracts' that last for a much longer time. Bromeliad inflorescences attract a range of animals for pollination including hummingbirds, bats, moths and butterflies. Their colourful inflorescences have also led to the popularity of bromeliads as ornamental plants. The basal bloomless part of the inflorescence is known as the scape. The scape usually bears scape bracts in a loose arrangement.

Leaves: Tank bromeliads possess specialised epidermal hairs modified for absorption called trichomes on the inner side of their leaf bases. The trichomes absorb water and dissolved nutrients impounded within the rosette. The leaves posses a waxy cuticle and are sometimes equipped with spines, which probably discourage herbivory.

Roots: The roots of most tank bromeliads are structually and functionally reduced. Their main purpose is to anchor the bromeliad to its host.

Offshoots: In addition to seed production bromeliads reproduce vegetatively by producing offshoots that grow between the axils of the basal leaves.

A few of the bromeliads found around Las Cuevas:

Aechmea bracteata, a medium sized epiphytic tank bromeliad.

Bromelia pinguin, a large terrestrial bromeliad protected by sharply toothed leaf margins.

Aechmea sp. a large epiphytic tank bromeliad.

Vriesea heliconioides, a small epiphytic tank bromeliad.