Derrick Posted February 28, 2014 Report Share Posted February 28, 2014 Bromeliad Ant-Plants: An Introduction. Most bromeliads are unique due to highly specialised adaptations that enable the storing of phytotelmata (aquaria-like water reserves) and/or they have trichome coated leaves that enable highly efficient intake of water and nutrients. Indeed, these are sometimes derived entirely from atmospheric sources. I add the cautionary word sometimes because many so-called 'airplants' derive some water and nutrients from organic derived leachates percolating down forest supports during rain or even heavy fog events. Yet, some airplant species are able to grow quite capably on inorganic supports such as tiled roofs or even electricity cables. Phytotelm (tank) bromeliads trap organics and atmospheric dusts in the centre of their leaf rosettes and/or leaf axils, thus enabling access to through-fall nutrients. As we will see, both phytotelm and tankless bromeliad types often provide homes to resident life forms both macro (usually arthropods or amphibians) and micro species (algae, cyanobacteria etc.,) and all help to supply plant nutrients. Bromeliad Taxonomic Changes. It has long been accepted that the Bromeliaceae had only three sub families, Pitcairnioideae with winged seeds, Tillandsioideae with plumose (feathery) seed and Bromelioideae having fleshy, fauna dispersed fruits. Now due to the results of DNA studies there is a new phylogeny for Bromeliaceae that creates an additional five sub-families. The resulting eight subfamilies are here listed in the order they are believed to diverge from their ancestral forms. (Givnesh et al. 2007.) Brocchinioideae are endemic to the ancestral Guyana Shield; type Brocchinia. Lindmanioideae are also endemic to the ancestral Guyana Shield; type Lindmania. Tillandsioideae are mostly air plants; sample genera Tillandsia, Vriesea. Hechtioideae have mostly xerophytic forms; type Hechtia. Navioideae are also endemic to the Guyana Shield but with one species found on the Brazilian Shield, sample genera, Brewcaria, Cottendorfia, Navia, Sequencia, and Steyerbromelia. Pitcairnioideae; sample genera, Abromeitiella, Deuterocohnia, Dyckia, Encholirium, Fosterella and Pitcairnia. Puyoideae is a sister clade to Bromelioideae, type genus Puya. Bromelioideae is a sister clade to Puyoideae; sample genera, Aechmea, Ananas, Cryptanthus, Bromelia and many others. It will probably take decades for this upheaval in the world of bromeliads to work its way into popular literature. However, having any clade (branch) of an evolutionary tree divulging at an earlier time does not necessarily mean its members are any more primitive than later divulging clades. Early phyletic branching does not mean that evolution has stopped, as we will see so definitely in Brocchinia. Bromeliad Eco-physiological Types. Professor David Benzing (2000) distinguishes five eco-physiological bromeliad forms, however because this was published prior to the above revision he only used the older sub family divisions. 1. Terrestrial herbs of subfamily Pitcairnioideae and many Bromelioideae that use roots to acquire water and nutrients due to their leaf trichomes being non-absorbent. 2. Terrestrial Bromelioideae with leaf bases that form rudimentary tanks into which some axillary roots may penetrate. 3. Terrestrial or epiphytic herbs in sub-family Bromelioideae with roots that are of little importance concerning water and nutrient intake. Leaf bases form extensive phytotelmata along with an obligate CAM pathway and possession of at least semi-absorbent trichomes. 4. Tank forming, mostly C3 epiphytes in subfamily Tillandsioideae and some Brocchinia (now in Brocchinioideae) with many highly efficient water and nutrient gathering trichomes on their leaf bases. Roots primarily acting only as hold fasts. 5. Tank less epiphytic or lithophytic, succulent/xerophytic Tillandsioideae with absorbent trichomes covering entire leaf areas. Roots, if any are hold fast only. Most ant mutualists fit here. Link to comment Share on other sites More sharing options...
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