We drifted and paddled down the swirling brown current, through the vivid rain-drenched green of the tropic forest. The trees leaned over the river from both banks. There were many kinds of palms. One type was the burity with stiff fronds like enormous fans, and another was called the bacaba, with very long, gracefully curving fronds. In places the palms stood close together, towering and slender. Their stems made a stately colonnade. Their fronds were arched fretwork against the sky. Butterflies of many hues fluttered over the river. The day was overcast, with showers of rain. When the sun broke through rifts in the clouds, his shafts turned the whole forest to gold." Glossary

palms: a group of tropical plants

frond: a long leaf with many small divisions

colonnade: a row of columns usually holding up a roof

fretwork: patterns or decoration on a surface made by cutting into or through a surface

arch: something that has a curved shape

What two things are being compared in the simile you chose?