What do you mean by "four gentlemen" in Flowers?

Plum, orchid, bamboo and chrysanthemum.

Chrysanthemum: Generally speaking, it means a calm and positive quality; Bamboo: stands for strong and uneven, stubborn and strong, positive wind; Orchid: it means simple and vulgar style; Plum blossom: Plum blossom is proud of snow, which means its unswerving and hardworking body.

Chrysanthemum morifolium is a perennial herb of Compositae, and it is one of the traditional Chinese medicines commonly used in China, mainly used for medicinal purposes of flower heads. Chrysanthemum is sweet and bitter, slightly cold in nature, and belongs to the lung and liver meridians, which has the effects of lowering blood pressure, improving eyesight and refreshing.