Tillandsioideae is a subfamily of plants in the bromeliad family

Bromeliaceae The Bromeliaceae (the bromeliads) are a family of monocot flowering plants of about 80 genera and 3700 known species, native mainly to the tropical Americas, with several species found in the American subtropics and one in tropical west Africa, ...

. This subfamily contains the greatest number of species (about 1,400). Most are epiphytic or lithophytic, growing in trees or on rocks where they absorb water and nutrients from the air. Spanish moss of the genus '' Tillandsia'' is a well-known species. Bromeliads in the genera '' Guzmania'' and ''

Vriesea ''Vriesea'' is a genus of flowering plants in the botanical family Bromeliaceae, subfamily Tillandsioideae. The genus name is for Willem Hendrik de Vriese, Dutch botanist, physician (1806–1862). Its species are widespread over Mexico, Central ...

'' are the more commonly cultivated members of this subfamily.

Description

Nearly all bromeliads have specialized

cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...

groups called trichomes which form scales on the

foliage A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, s ...

. The trichomes occurring on Tillandsioideae may cover the plants so completely that they appear grey or white, like Spanish moss. In addition to absorbing nutrients, the trichomes may serve to insulate the plant from freezing weather. Plants in this group have smooth or entire leaf margins, unusual color and markings, with many producing fragrant flowers. All their leaves are spineless (unarmed) and 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 derived with special adaptations for survival in very dry conditions, with many described as

xerophyte A xerophyte (from Greek ξηρός ''xeros'' 'dry' + φυτόν ''phuton'' 'plant') is a species of plant that has adaptations to survive in an environment with little liquid water, such as a desert such as the Sahara or places in the Alps or the ...

Taxonomy

Phylogeny and classification

Tillandsioideae is the largest of the subfamilies of the family Bromeliaceae, with upwards of 1,400 species.

Molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

studies from 1997 onwards repeatedly showed the monophyly of the subfamily. However, the division of the subfamily into genera has varied considerably. A 1997 monograph used six genera: ''Catopsis'', ''Glomeropitcairnia'', ''Guzmania'', ''Mezobromelia'', ''Tillandsia'' and ''Vriesea''. Other genera were later segregated from ''Tillandsia'' and ''Vriesea'', of which three, ''Alcantarea'', ''Racinaea'', and ''Werauhia'', gained general acceptance. Molecular phylogenetic studies from 2001 onwards showed that ''Mezobromelia'', ''Tillandsia'' and ''Vriesea'' in particular were not monophyletic, and that the

circumscription Circumscription may refer to: *Circumscribed circle *Circumscription (logic) *Circumscription (taxonomy) * Circumscription theory, a theory about the origins of the political state in the history of human evolution proposed by the American anthrop ...

of other accepted genera was problematic in relation to these three genera. A major monograph published in 2016 used plastid and

nuclear DNA Nuclear DNA (nDNA), or nuclear deoxyribonucleic acid, is the DNA contained within each cell nucleus of a eukaryotic organism. It encodes for the majority of the genome in eukaryotes, with mitochondrial DNA and plastid DNA coding for the rest. It ...

as well as morphological characters to produce a new phylogeny and classification for the subfamily. Their preferred cladogram is shown below. The 2016 study was unable to fully resolve the two genera ''Cipuropsis'' and ''Mezobromelia'' because the type species of ''Cipuropsis'', '' Cipuropsis subandina'', was not available for study. In 2017, Gouda added a new species to ''Cipuropsis'' ('' Cipuropsis asmussii'') and clarified the distinction between ''Cipuropsis'' and ''Mezobromelia'', leaving the former with three species. , the Encyclopaedia of Bromeliads accepted both genera, as well as the closely related ''Josemania'', whereas Plants of the World Online treated all three in the single broadly defined genus ''Cipuropsis'' – marked as ''Cipuropsis'' s.l. on the cladogram above. ''Waltillia'' was not included in the 2016 study as a separate genus, but is accepted by both the Encyclopaedia of Bromeliads and Plants of the World Online. The classification produced by the 2016 monograph uses four tribes, Catopsideae, Glomeropitcairnieae, Tillandsieae and Vrieseeae, the last of which is divided into two subtribes, Cipuropsidinae and Vrieseinae.

Genera

Genera placed in the subfamily by the Encyclopaedia of Bromeliads are listed below. Plants of the World Online did not accept ''Josemania'' and ''Mezobromelia'', sinking them into ''Cipuropsis''. Tribe and subtribe placements are from the 2016 monograph and the Encyclopaedia of Bromeliads.

References

* * * Luther, H. E. (2008
An Alphabetical List of Bromeliad Binomials, Eleventh EditionThe Marie Selby Botanical Gardens
Sarasota, Florida, USA. Published b
The Bromeliad Society International

External links

{{Taxonbar, from=Q137236 Commelinid subfamilies