It's the world's biggest flower, and maybe the stinkiest too. Now scientists have used genetic analysis to solve the longoutstanding mystery of the lineage of the rafflesia flower, known for its blood-red bloom measuring 1m wide and its nauseating stench of rotting flesh.

Writing in the journal Science, a team of researchers said rafflesia - discovered in an 1818 scientific expedition to a Sumatran rainforest - comes from an ancient family of plants known not for big flowers, but for tiny ones.
In fact, many of its botanical cousins boast flowers just a few millimeters wide. This family, called Euphorbiaceae, also includes the poinsettia, Irish bells and crops such as the rubber tree, castor oil plant and cassava shrub, the researchers said.
Rafflesia's many odd characteristics long had tripped up scientists trying to figure out where it fit on the botanical tree of life. It is sort of a botanical outlaw - a parasitic plant that steals nutrients from another plant while deceiving insects into pollinating it.
Rafflesia (pronounced rah-FLEZZ-ee-ah) lives inside the tissue of a tropical vine related to the gravevine, with only its flower visible. It is devoid of leaves, shoots and roots, and does not engage in photosynthesis, the process plants use to exploit the energy from sunlight.
Its flower can weight 7kg. They are blotchy blood red. They smell like decaying flesh and can emit heat, perhaps mimicking a newly killed animal in order to entice the carrion flies that pollinate it.
There are various species of rafflesia growing on the floor of rainforests in parts of South-East Asia. It is said its lineage dates back roughly 100million years to the Cretaceous period, the last act of the age of dinasours when flowering plants are believed to have first appeared. The researchers determined that over a span of 46 million years, rafflesia's flowers evolved a 79-fold increase in size before assuming a slower evolutionary pace.