The leaf symbolises the spear.
The five anthers, the five wounds.
The tendrils, the cords or whips.
The column of the ovary, the pillar of the cross. The stamens, the hammers.
The three styles, the three nails.
The fleshy threads within the flowers, the crown of thorns. The calyx, the glory or nimbus.
The white tint, purity.
The blue tint, heaven.
It keeps open three days; symbolising the three years' ministry. (Matt. xii. 40.) (See Pike's Head.)
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894