Plants by some measures represent the greatest diversity of life on the planet (in the universe?) From single-celled algae to massive sequoias, they span nearly the entire range of sizes. (Prokaryotes are smaller, but who's counting?) They embrace the barely-differentiated slime of algae to the highly structured flowers and vascular systems of flowering plants. They dominate every continent on earth in biomass. They are second only to insects in diversity of genera and species. As I said: an impressive group of critters by any standards. But we're a curious species with a thirst for gossip and scandal: which are the weirdest of the weird?
Perhaps it's Wolffia, the world's smallest flower less than 1mm long, lacking roots, petals, leaves, and nearly everything else one normally associates with plants. [1] Or do you prefer the corpse flower (Rafflesia arnoldii), the world's largest flower -- almost a meter wide and weighing in at up to 11kg... and quite possibly the foulest smelling living thing into the bargain! [2]
Maybe the carnivorous plants are more sensational, such as the ever-popular venus fly-trap (Dionaea muscipula). [3] But fly-traps take a full tenth of a second to snap shut. Granted, that's a respectable time for a kingdom that typically never moves at all in a full lifetime, but plants can do better. The record, according to wikipedia, is the white mulberry tree (Morus alba), whose flowers release pollen at speeds up to half the speed of sound. [4]
Then there's always the oldest organism on earth, a specimen of Pinus longaeva in the Bristlecone Pine Forest of eastern California (about 4700 years old, as of April 2007). But some stands of aspen and creosote bush might argue the point, as they form clonal colonies that can extend back tens of thousands of years. [5]
There are entire ecosystems of plants specially adapted not only to survive periodic fires, but to actively encourage them. For example, sagebrush (Artemisia) a dominant member of the southern Californian chaparral -- contains volatile oils in its leaves. After fire has spread literally explosively throughout the mountainside, taking all the competition with it, sagebrush handily sprouts right back up from protected root crowns. [6] Other species, such as many pines and even to some extent the giant sequoia (Sequoiadendron giganteum) actually require fire in order for their cones to open and release seeds. [7] [8]
Some plants, such as the monotropes (Monotropoideae), some orchids (e.g. the coral roots (Corallorrhiza)), and the liverwort Cryptothallus, have completely lost the ability to photosynthesize. Instead they live off of decaying plant matter... or rather, they parasitize fungi which do so, a subtle point only relatively recently discovered. [9]
The Ginkgo biloba looks like a perfectly normal tree, yet taxonomists have placed it by itself in its own private genus, family, order, class, and even division! What makes this living fossil so different from all other living plants? You'll have to ask the taxonomists it seems to be in the details of the "fruit" and the fertilization technique it uses. Currently it is known to grow wild only in two very small locations in eastern China a fine example of a tree that is very happy our species came along, as thanks to us, it now grows in cultivation throughout the world! [10]
The Wollemi pine (Wollemia nobilis) is another fossil species. Discovered in 1994, there are fewer than 100 trees living in the wild in a few remote canyons in the Blue Mountains of Australia. Its closest relatives are some two million year old fossils. It just goes to prove that, even in today's age when we are prone to assume everything important has already been discovered, there are still big surprises hiding within 100 miles of one of the world's largest cities! [11]