Ironically named ‘Star of Bethlehem’ orchid supports Darwin’s theory of evolution

<blockquote><strong>Orchid supports evolution theory at the Botanic Gardens</strong>
 
An example of the genius of Charles Darwin’s theory on evolution is currently in flower in the guise of an orchid, the Star of Bethlehem, at Sydney’s Royal Botanic Gardens.
 
Botanic Gardens Trust Executive Director, Dr Tim Entwisle said Darwin predicted 41 years before its discovery that a pollinator had to exist to ensure the survival of the orchid.
 
“The Star of Bethlehem was discovered in Madagascar in the 1860s.  Its unique because it stores nectar at the bottom of a tube up to 30 centimetres (12 inches) long,” Dr Entwisle said.

“Darwin saw the extraordinary flower with its very thin and long tube and believed an animal had to have evolved to enable it to reach the nectar and ensure the plant’s survival.
 
“In 1903, 21 years after Darwin’s death, the mysterious pollinator was found – supporting  Darwin’s theory of evolution.  The pollinator was a hawk moth with a proboscis long enough to reach the bottom of the orchid’s nectar tube or ‘spur’.  It was named Xanthopan morganii praedicta – to honor Darwin’s prediction.

“It’s clear the moth and orchid evolved together, starting with an orchid with a small tube and a moth with a small tongue and over time they both grew longer and longer,” he said. “It’s all about competition for food and pollination.”

The Star of Bethlehem (Angraecum sesquipedale) is currently blooming at the Tropical Centre at Sydney’s Royal Botanic Gardens. All up there are approximately 232 tropical orchids in the Tropical Centre and over 1,000 other orchid species grown outdoors.
 
Dr Entwisle said the orchid family is one of the largest plant families in the world and many varieties are suitable for planting in home gardens.
 
“There are around 107 orchid genera containing more than 800 species growing in Australia – most unique to the country.  Many are suitable for home gardens,” he said.
 
“Each orchid has particular requirements, but most like a moist, free-draining mix, and prefer semi-shade or filtered light and good air flow.  Orchid plants will live for many years if their conditions are right and there are no pests.

“There are two types of orchids, epiphytes which grow on trees and terrestrial which grow on the ground.  In Australia, the less flamboyant terrestrial species outnumber the epiphytes three to one,” Dr Entwisle said.

<strong>The Tropical Centre is open daily from 10am until 4pm, a fee applies for entry – $8.80 for families (2 adults/2 children), $4.40 for adults, $3.30 for seniors and $2.20 for children or concession.  Entry to the Royal Botanic Gardens is free.</strong></blockquote>