'A shrub' or 'plant,' as in Genesis 21:15, denotes perception, but so little that it is hardly anything, in same way as 'trees,' but to a lesser degree. So 'to be cast under one of the shrubs,' signifies being destroyed regarding truth and good, to the point of desperation.

(References: Arcana Coelestia 2682 [1-3])

'To cover under wings,' as in Psalms 91:4, signifies guarding with the divine truth, which is the divine spiritual. 'Wings' signify spiritual truths. 'Wings,' when related to the Lord, signify the divine spiritual. In the opposite sense, 'wings' relate to falsities and rationalizations from them.

(References: Apocalypse Revealed 245; Deuteronomy 32:10-12; Divine Providence 20-25; Ezekiel 16:8; Malachi 4:2; Matthew 23:37; Psalms 17:8, 26:8, 57:2, 63:8)