Photo: George O. Poinar, Jr.
They say time really does stand still; at least when it comes to fossils. And last week, scientists announced that two tropical flowers, possibly as old as 45 million years, have been found in two separate pieces of amber. The ancient flowers, which were discovered in a cave in the Dominican Republic, offer fascinating clues about the evolution of life on the planet. Considering our own brief time here on earth, the discovery certainly puts things into perspective.
Eerily immortalized in two golden yellow-orange stones, the flower fossils were unearthed in the Cordillera Septentrional, a mountain range that runs parallel to the north coast of the tropical island. The fully intact, trumpet-shaped flowers feature corollas and stamens and a single filament-like style (which protrudes from the mouth of each flower). The petals are covered in tiny protective hairs.
Photo: Nature Plants
While Dominican amber has yielded up plant remains before, it’s been hard for researchers to identify specific species since bits of floral and plant structures are often located in separate pieces of amber. This marks the first time a perfectly preserved flower has been discovered. Scientists believe the ancient flowers’ pristine condition indicates the blossoms were likely blown off the plant quickly before becoming trapped in the tree’s resin. Usually, flowers decay rapidly once they’ve bloomed, causing their structures to be dispersed.
The flowers are so perfectly preserved, in fact, that according to Oregon State biologist George Poinar, one of the co-authors of the study published in Nature Plants, they look like they might have literally just fallen off the tree.
Photo: George O. Poinar, Jr.
Poinar and Rutgers-based Dr. Lena Struwe (the other co-author) believe these are the first fossilized examples of a flower belonging to the Asterid clade of flowers (a group that includes an ancestor and all of its descendants.) Asterids are one of the world’s three major evolutionary groups of flowering plants. The large family includes the groups Asteraceae, Lamiaceae and Solanaceae, which comprise asters and daisies, mint, coffee, potatoes, tobacco and tomatoes, among other plants.
The ancient flower is believed to fall into a smaller Asterid family called Loganiaceae, which includes subtropical and tropical herbs, shrubs, trees and vines. Several Loganiaceae plants, including Strychnos nux-vomica are the sources of poisons like strychnine.
Strychnos nux-vomica, Strychnine plant
Is the ancient flower poisonous? Hard to say, since the strychnos genus of tropical woody plants contains a couple hundred of species, only a small portion of which are lethal. Scientists are certain, however, that the flowers must have bloomed sometime between 15 and 45 million years ago, during the mid-Tertiary period. This was a time in our geological history long before there was a land mass connecting South America and North America and when much of the earth’s climate was tropical or sub-tropical.
Supporting this theory is the fact that the flowers are encased in the resin of a large tropical tree (now extinct), called Hymenaea protera. The evergreen leguminous tree grew in abundance on the combined South American and African continents during the Tertiary geologic period. Most, if not all of Dominican amber, comes from the resin of this large tree, which formed part of the upper story of the prehistoric tree canopy.
(Hymenaea protera is the probable ancestor of the present-day Hymenaea species, a tree common to the Caribbean and Central and South America.)
You have to admit, the strychnine plant looks an awful lot like the ancient flower. Struwe, who is an expert on asterids of the genus strychnos, believes that although it is similar, the flower is an entirely new species. Given what is known about the mid-Tertiary period, it most likely was borne by plants that lived in a steamy tropical forest that included a mix of large and small trees, climbing woody vines, palms and other vegetation. The flower may have been creamy white or yellow, like strychnos.
In honor of its amber origin, the new species has been named Strychnos electri, after the Greek word elektron, meaning amber.