Ron laughed at that, but then got to business. He did in fact know the Sunlight Charm, which Professor Sprout had mentioned in class and Ron's study group had looked up. Parvati had figured it out first and showed everyone else, and Ron had been close to last to get it (Charms still wasn't his strong point), but he had learned. He pointed his wand at the ceiling of plants above them, inscribed a circle with it, and said, "Lumos solem!" 