National Geographic : 1977 May
Aggressive colonizers, red mangroves owe their far-flung presence to seagoing seeds that germinate while still on the tree. The flowers (left) bloom for a few weeks in the spring and then fall, making way for a fruit (top) that harbors a single seed embryo. A seedling shoot soon sprouts from each fruit (above) and grows to a length of six to twelve inches before dropping from the tree. Falling on land, it may put down roots immediately; other wise, it will float with the current in a horizontal position. Gradually the root tip becomes water logged, causing the seedling to shift upright. In this manner it may drift for many months be fore going aground in shallow water, where it can take root (above). Borne on equatorial currents, seedlings have even crossed the Atlantic. As the tree matures (below), its prop roots take in oxygen, and transmit moisture and nutrients to the trunk and branches. They may also trap silt and debris that aid in stabilizing the shoreline.