primary rachis branch

例句：

1. 1. The tree's primary rachis branch is visible from the top of the hill.
   从山顶上可以看到这棵树的主要分枝。
2. 2.The scientist studied the plant's primary rachis branch to understand its growth patterns.
   科学家研究了植物的主要分枝，以了解其生长模式。
3. 3. The forestry department identified the primary rachis branch as a critical habitat for rare species.
   林业部门将主要分枝识别为稀有物种的关键栖息地。