Guess: What kind of plant is described by "straight outside, straight mind, like a valley": bamboo.
bamboo, also known as bamboo. There are many varieties, such as Phyllostachys pubescens, Dendrocalamus latiflorus, Fargesia lanceolata and so on. Perennial Gramineae Bambusoideae(Bambusaceae stems are mostly woody and herbaceous, is the fastest growing plant in the world. Bamboo is very tough and many materials are made of bamboo.
Usually, it grows by creeping roots in the ground, or it can be propagated by flowering and seed setting. The seed is called bamboo rice. Some kinds of bamboo shoots are edible. Bamboo sticks are tall and straight, slender, green all the year round, proud of snow and frost, and are loved by China people. Together with Mei, Lan and Ju, they are called "four gentlemen in flowers", and together with Mei and Song, they are called "three friends in cold years". From ancient literati, there are many people who love bamboo, and many bamboos originated in China, which is also called the cultural relics symbol of China.
Bamboo is noble, elegant and handsome. In ancient times, it was often used to describe upright and unyielding figures, such as Qu Yuan and Wen Tianxiang. It shows that it is proud of its clank and is not afraid of cold and heat, wind, frost and snow, so it is deeply loved by our people.