1. Initial Floral Transformation: At the beginning, Algernon's flowers had bloomed with vivid colors and were thriving. This represented his intellectual growth and transformation brought on by the experimental treatment.
2. Fading and Wilting: As the progress begins to reverse, the flowers start to lose their vibrancy and luster. The petals show signs of wilting, and the bloom begins to diminish, symbolizing the decline of Algernon's mental abilities.
These two details - the initial beauty and subsequent fading of the flowers - effectively capture the essence of Algernon's story and reflect the poignant reversal of his progress.