"And the stars and the trees bow in adoration" [al-Rahman: 6]. The star (al-najm): that which is of plants without a stalk, and the tree (al-shajar): that which is upon a stalk. Their bowing in adoration is their shadows.
Muhammad said: It is said, 'The plant grew (najama), it grows (yanjumu) in growth (nujuman),' and 'The herb sprouted (baqala), it sprouts (yabqulu) in sprouting (buqulan).'