the typical vascular cylinder of a dicotyledonous plant or a gymnosperm, consisting of a ring of collateral bundles of xylem, cambium, and phloem. Origin of eustele.
Tap water is fine in Barbados, go in any restaurant and they will ask if you want water then give a choice of bottled or tap. They wouldn't be doing that if the water was bad. It is one of the few places around the world that I will drink tap water. I certainly don't drink it in the UK.
Water is generally safe to drink in Spain. Madrid is perhaps one of the safest places to drink water from the tap. The tap water in Barcelona and surrounding is not known for its taste. If travelling in remote areas, it is best to play it safe and drink bottled water.