紫茎（Ｓｔｅｗａｒｔｉａｓｉｎｅｎｓｉｓ）为山茶科紫茎属落叶小乔木。树高可达１５米。树皮常呈灰黄色，因所处环境不同，其树皮有时也呈红褐色或黄褐色，树干光滑，有些地方群众因此称其为“红木”、“赤膊柴”。大树树皮有明显的片状剥落现象。嫩枝有绒毛，小枝红褐色； Stewartiasinensis is a genus of the genus Camellia. Tree height up to 15 meters. Bark often gray-yellow, because of the different environment, the bark sometimes reddish brown or brown, smooth trunk, so some local people called it “mahogany”, “Chi Fu Chai.” Big tree bark has obvious flaking phenomenon. Young branches have hair, branchlets red-brown;