Ja·cob's ladder 
(jākəbz)
(jākəbz)n.
1. Nautical A rope or chain ladder with rigid rungs.
2. Any of various plants of the genus Polemonium, especially P. caeruleum, having bell-shaped usually blue flowers and alternate, pinnately compound leaves with numerous leaflets.
[From the ladder seen by the biblical patriarch Jacob in a dream (Genesis 28:12).]