丛 means a clump or thicket (
花丛 'cluster of flowers',
草丛 'tall grass',
树丛 'thicket');
丛中 attaches
中 ('inside') to mean 'inside the cluster/thicket'. Famously appears in Mao Zedong's poem 《
卜算子·
咏梅》:
待到山花烂漫时,
她在丛中笑 - 'When mountain flowers are in full bloom, she smiles among them.'
