The doodle on the left on the bottom is the cross-section of the trunk from one type of snail-leaf bush known as the fountain tree. It has specialized roots that suck up water continually and expel it out of holes all over the tree, keeping the whole organism moist. It rains constantly underneath these trees even without a cloud in the sky, much to the surprise of several explorers. Clay and other compounds in the water build up on the trunk and branches, forming a protective layer to keep out certain parasites.
The doodle on the right on the bottom is the tiny fruit of one species of fountain tree, with the seed to one end of it.