TAXONOMY (Science of classifying plants)
Closely related species are grouped into a genus.
Genus names are always in capitals eg Neoregelia. Species names always start with a lower case eg Neoregelia carolinae. Hybrids are in capitals & single quotes eg Neoregelia ‘Purple Star’.
The bromeliad family of plants contains over 3000 well described species in approximately 57 genera. As well there are thousands of hybrids, many registered as well as many unregistered. They are divided into three sub groups related to their genetic similarities:
Pitcairnioideae (pit-cairn-ee-oy-dee-eye): With a few exceptions, all of the members of this subfamily are either terrestrial (grow in the ground) or saxicolous (grow on or among rocks). Common to arid & high altitude regions, this family contains the most ancient bromeliads, more closely resembling its grassy relatives than the bromeliads in the other subfamilies. The commonly cultivated genera in this group include Dyckia, Hechtia, Pitcairnia & Puya.
Most have fleshy leaves with heavily spined edges & resemble Agave. Their blooms contain dry capsules with small, wingless seeds. Unlike most other bromeliads, this group has a developed root system to gather water & nutrients. Thus not all leaves grow in a cup formation to catch water as in the other subfamilies. Leaf trichomes (specialised cell groups which form scales on the leaves) are present but not as effective in gathering nutrients. They can however be thick enough to provide a frost barrier (eg Puya laxa).
There are over approx 1030 species in 16 genera which are: Brewcaria, Brocchinia, Connellia, Cottendorfia, Deuterocohnia, Dyckia, Encholirium, Fosterella, Hechtia, Lindmania, Navia, Pepinia, Pitcairnia, Puya, Sequencia & Steyerbromelia. There is one other genus that is classified in this subfamily called Ayensua (there is only one species which is deciduous = Ayensua uaipanensis).
Tillandsioideae (til-land-see-oy-dee-eye): This group contains the greatest number of species (approx 1,277) but the fewest genera (9). It accounts for about 40% of the known bromeliads.
Most are epiphytic (plants that absorb water and nutrients from the air and rain) or lithophytic (grow on rocky or stony ground) & thus grow in trees or on rocks.
The trichomes occurring on Tillandsioideae may cover the plants so completely that they appear grey or white like ‘Spanish Moss’ (Tillandsia usneoides). In addition to absorbing water & nutrients, the trichomes may serve to insulate the plant from frosts.
Bromeliads in this group have smooth leaf edges, unusual colour & markings, with many producing fragrant flowers. All their leaves are spineless & their fruit is a dry capsule containing winged seeds which are usually dispersed by breezes. Feathery seed plumes help them to adhere to a suitable epiphytic surface for germination. This subfamily is probably the most evolved with special adaptations for survival in very dry conditions, with many described as xerophytes (plants adapted to living in a dry, arid habitat).
The genus Tillandsia is the largest in this subfamily accounting for approximately 600 of the species. The genera in this group are: Alcantarea, Catopsis, Glomeropitcairnia, Guzmania, Mezobromelia, Racinaea, Tillandsia, Vriesea & Werauhia.
Bromelioideae (bro-meel-ee-oy-dee-eye): This subfamily is the most diverse & contains the most genera (32) but the least species (approx 1140). Most are epiphytes, though some have evolved in, or will adapt to terrestrial conditions.
They generally have spiny leaves & most grow to form a rosette with a water holding tank.
The genera in this group are: Acanthostachys, Aechmea, Ananus, Androlepsis, Araeococcus, Billbergia, Canistropsis, Canistrum, Cryptanthus, Deinacanthon, Disteganthus, Edmundoa, Eduandrea, Fascicularia, Fernseea, Greigia, Hohenbergia, Lymania, Neoglaziovia, Neoregelia, Nidularium, Ochagavia, Orthophytum, Portea, Pseudaechmea, Pseudananus, Quesnelia, Ronnbergia, Ursulaea & Wittrockia.