«وقد لاح في الصبح الثريا كما ترى كعنقود ملاحية حين نورا»
The Pleiades appear at dawn like a blossoming cluster.
The verse does not merely compare the color of one star with one flower. It presents many small bright elements grouped in a particular arrangement. To call the point of resemblance simply “whiteness” would miss the configuration that makes the comparison striking.
The source uses this kind of image to develop the idea of a composite sensory appearance (هيئة مركبة). Individual components may be visible, but the comparison concerns the way they form a unified scene.