Bromeliads are a varied group of plants, adapted to a number of climates.
All bromeliads are composed of a spiral arrangement of leaves called a ‘rosette’.
The bases of the leaves in the rosette may overlap tightly to form a ‘tank’ or water reservoir. These ‘tank bromeliads’ rely less heavily on their roots for water and nutrient absorption and are more often found as epiphytes.
The more ancient terrestrial bromeliads don’t have this water storage capacity and rely primarily on their roots for water and nutrients.
There are also the non-tank epiphytes like the grey leaved Tillandsias that gather water and nutrients only from the leaf trichomes.
The foliage takes different shapes, from needle thin to broad and flat, symmetrical to irregular, spiky to soft.
The foliage is the most widely patterned and coloured of any plant in the world.
All bromeliad have trichomes (scales) which serve as a very efficient absorption system. In the desert, they help reduce water loss and shield the plants from solar radiation. These plants are so heavily covered that they appear silvery-white. On many species (especially in more humid areas), the scales are smaller and less noticeable. Sometimes they form patterns and banding on the leaves.
The inflorescence (group of flowers arranged on a stem called a scape) is also regarded as considerably more diverse than any other plant family. Some reach up 10 metres tall while others are as small as 2-3 mm. With few exceptions, they are produced from the centre of the rosette. They may be branched or simple, retaining their colour from several weeks to 12 months. The scape may be long with the flowers held away from the plant (e.g. Alcantareas) or it may be short with the flowers nestled in the rosette (e.g. Neoregelias).
Root systems vary from terrestrial species with complex root systems to epiphytic species with hard wiry roots to attach to trees and rocks.
Some bromeliads are faintly scented while others are heavily perfumed (Tillandsia cyanea resembles the smell of clove spice).
The largest bromeliad is Puya raimondii, which reaches 3-4 metres tall with a flower spike 10 - 12 metres tall and the smallest is probably Tillandsia usneoides