Scholars(主词) (who once thought Native American literatures were solely oral narratives recorded by missionaries or anthropologists) now understand(动词) this body of work(名词片语做动词understand受词) to consist of(动词片语修饰后面的名词片语) both oral literatures and the written works of Native American authors(名词片语)
Understand 只是这句话的动词,主词是scholars,跟后面的to consist of 没有直接关系.

我也疑惑。。。
@贵阳新思路英语