Taxonomy

Taxonomy (systematics) is the science of classifying plants and animals by evaluating shared features and organizing them into a hierarchy based on these relationships. The basic taxonomic units or taxa (singular: taxon) are species. Every species is given an internationally recognized two part name (binomial) by which it is known. The first part of this name is called the Genus and the second part the Species. More closely related plants within the family, which share some general/generic features, are grouped in the same genus thus the genus/species describe the taxon generically/specifically. Unlike common names which can vary from region to region, a species' binomial name is unique and precise. The name is usually derived from Latin or Greek (or a modern word that has been Latinized). Genus names are always capitalized and species names always start with a lower case letter. Species names often are descriptive (xanthocalyx - with yellow flowers), indicate a place of origin (brasiliensis - from Brasil), or are honorific, named after the collector or other person worthy of the the honor of being immortalized in the taxonomic nomenclature (fosteriana - in honor of Mulford Foster).

Family: Bromeliaceae

Bromeliads belong to the family Bromeliaceae and are members of the Class Liliopsida (monocots). Monocots comprise one quarter of all flowering plants and include some of the largest and most well known groups of plants: orchids, palms, grasses. Traditionally the family Bromeliaceae has been divided into three subfamilies: Pitcairnioideae, Bromelioideae and Tillandsioideae.

Pitcairnioideae

This subfamily contains the most ancestral bromeliads and many resemble the grass family from which they evolved. Almost all are terrestrial and rely on an extensive root system for their moisture and nutrients. They are generally spiny leaved and have dry capsules with small wingless seeds.

Bromelioideae

This subfamily is the most diverse containing the greatest number of genera (but the least number of species). Most species in this subfamily are epiphytic and characterized by a rosette-like form many forming a water holding tank. They generally have spiny leaves and berry like fruits containing wet seeds which are often distributed by birds and animals who consume the fruits.

Tillandsioideae

This subfamily contains very few genera but includes the most number of species. Most of the members of this subfamily are epiphytes. All have spineless leaves and their fruit is a dry capsule containing winged seeds which are usually dispersal by breezes. The feathery plumes also help the seed to adhere to a suitable epiphytic surface for germination. This subfamily has special adaptations for survival in very dry (xeric) conditions.
Recent studies (most prominently the one cited below) have used DNA analysis to examine the relationship between the genera of Bromeliaceae. The results confirmed that the Tillandsioideae and Bromelioideae subfamilies are monophyletic (derived from a single ancestral form). Pitcairnioideae, however, was found to be paraphyletic and required five new groups to be split from it in order for Pitcairnioideae and the newly created subfamilies to all be monophyletic as well. This new reorganization of the genera within the most ancestral subfamily (Pitcairnioideae) hopefully now comes closer to representing their true evolutionary (phylogenetic) relationships.

As part of the DNA sequencing it was determined that the monospecific genus Ayensua (containing only Ayensua uaipanensis) actually belonged in the genus Brocchinia. Additionaly, another troublesome species (Brocchinia serrata) was found to have no relation to the other members of its genus and was separated into a newly created genus Sequencia. So while Ayensua was lost in the new organization the number of genera remains at 58 with the addition of Sequencia (the name a tribute to its origin as a result of DNA sequencing).

A PDF version of the research paper describing these DNA-based changes to the taxonomy of the bromeliad family can be found on the University of Wisconsin's website by following the link below:

Givnish TJ, Millam KC, Berry PE, Sytsma KJ. 2007. Phylogeny, adaptive radiation, and historical biogeography of Bromeliaceae inferred from ndhF sequence data. Pp. 3-26 in JT Columbus, EA Friar, JM Porter, LM Prince, MG Simpson (eds.) Monocots: Comparative Biology and Evolution Poales. Rancho Santa Ana Botanic Garden, Claremont, CA.

Genera by Subfamily

Taxonomists continue to work on the bromeliad family, describing new species (and sometimes reducing an existing species to synonymy with another species). Occasionally a new genus will be described or a subgenus will be elevated to the rank of genus and other times an entire genus will disappear, incorporated into another genus. Any taxonomic listing must be viewed as the current state of the art in an ongoing process of refinement. The listing shown here follows LUTHER (2008). Additional information about bromeliad genera can be found in AN ANNOTATED CATALOG OF THE GENERIC NAMES OF THE BROMELIACEAE by Jason R. Grant.

TRADITIONAL BROMELIACEAE
Pitcairnioideae (16) Tillandsioideae (9) Bromelioideae (32)
Brewcaria
Brocchinia
Connellia
Cottendorfia
Deuterocohnia
Dyckia
Encholirium
Fosterella
Hechtia
Lindmania
Navia
Pepinia
Pitcairnia
Puya
Sequencia
Steyerbromelia
Alcantarea
Catopsis
Glomeropitcairnia
Guzmania
Mezobromelia
Racinaea
Tillandsia
Vriesea
Werauhia
Acanthostachys
Aechmea
Ananas
Androlepis
Araeococcus
Billbergia
Bromelia
Canistropsis
Canistrum
Cryptanthus
Deinacanthon
Disteganthus
Edmundoa
Eduandrea
Fascicularia
Fernseea
Greigia
Hohenbergia
Hohenbergiopsis
Lymania
Neoglaziovia
Neoregelia
Nidularium
Ochagavia
Orthophytum
Portea
Pseudaechmea
Pseudananas
Quesnelia
Ronnbergia
Ursulaea
Wittrockia

Based on the latest DNA study the Tillandsioideae and Bromelioideae subfamilies would remain the same (as shown above) but the genera in the former Pitcairnioideae subfamily would now more properly be organized into subfamilies as shown below:

FORMER PITCAIRNIOIDEAE
Brocchinioideae Lindmanioideae Hechtioideae Navioideae Pitcairnioideae Puyoideae
Brocchinia
Connellia
Lindmania
Hechtia
Brewcaria
Cottendorfia
Navia
Sequencia
Steyerbromelia
Deuterocohnia
Dyckia
Encholirium
Fosterella
Pepinia
Pitcairnia
Puya

A brief Genera Etymology is available describing the sources of the names of the currently recognized bromeliad genera. Derek Butcher has a binomial and synonym list that he maintains on the Bromeliad Society of Australia web site that lists the species in the Bromeliaceae family. Wikipedia now also has a complete listing of Bromeliads.


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