[Illustration: BAOBAB TREES AT MANAAR.] CHAPTER XII. GIANT TREES AND CHARACTERISTIC FORMS OF TROPICAL VEGETATION. General Remarks--The Baobab--Used as a Vegetable Cistern-- Arborescent Euphorbias--The Dracæna of Orotava--The Sycamore-- The Banyan--The sacred Bo-Tree of Anarajapoora--The Teak Tree-- The Saul--The Sandal Tree--The Satinwood Tree--The Ceiba-- The Mahogany Tree--The Mora--Bamboos--The Guadua--Beauty and multifarious Uses of these colossal Grasses--Firing the Jungle-- The Aloes--The Agave americana--The Bromelias--The Cactuses--The Mimosas--Bush-ropes--Climbing Trees--Emblems of Ingratitude-- Marriage of the Fig Tree and the Palm--Epiphytes--Water Plants-- Singularly-shaped Trees--The Barrigudo--The Bottle Tree--Trees with Buttresses and fantastical Roots--The Mangroves--Their Importance in Furthering the Growth of Land-Animal Life among the Mangroves--‘Jumping Johnny’--Insalubrity of the Mangrove Swamps-- The Lum Trees with formidable Spines. Wherever in the tropical regions periodical rains saturate the earth, vegetable life expands in a wonderful variety of forms. In the higher latitudes of the frozen north, a rapidly evanescent summer produces but few and rare flowers in sheltered situations, soon again to disappear under the winter’s snow; in the temperate zones, the number, beauty, and variety of plants increases with the warmth of a genial sky; but it is only where the vertical rays of an equatorial sun awaken and foster life on humid grounds that ever-youthful Flora appears in the full exuberance of her creative power. It is only there we find the majestic palms, the elegant mimosas, the large-leafed bananas, and so many other beautiful forms of vegetation alien to our cold and variable clime. While our trees are but sparingly clad with scanty lichens and mosses, they are there covered with stately bromelias and wondrous orchids. Sweet-smelling vanillas and passifloras wind round the giants of the forest, and large flowers break forth from their rough bark, or even from their very roots. The number of known plants is estimated at about 200,000, and the greater part of this vast multitude of species belongs to the torrid zone. But if we consider how very imperfectly these sunny regions have as yet been explored--that in South America enormous forest lands and river basins have never yet been visited by a naturalist--that the vegetation of the greater part of Central Africa is still completely hidden in mystery--that no botanist has ever yet penetrated into the interior of Madagascar, Borneo, New Guinea, South-Western China, and Ultra-Gangetic India--and that, moreover, many of the countries visited by travellers have been but very superficially examined--we may well doubt whether even one fourth part of the tropical plants is actually known to science.