This group of Angiospermous flowering plants is divided into a great number of natural groups or "orders." Of these there are about 275, and they are grouped in two sets or classes, which are separated one from another, as we shall hereafter see, by differences as to their modes of growth, the structure of their seeds, the numbers of the parts of their flowers, and the course of the veins in their leaves. First amongst the Angiospermous flowering plants may be mentioned the grasses forming the order _Gramineæ_, including under that term the tree-like bamboos (of multitudinous uses), with the rice plant, and all the grain-bearing herbs, all of which are grasses. Thus, with much reason may it be said of man, that "all flesh is grass;" for with the exception of the piscivorous Esquimaux, the exclusively flesh-eating Gouchos, the population of Australia, and the people of the Molluccas who nourish themselves on sago--which is the produce of a palm--with these and a few more exceptions, the staple food of the human race is one or another form of grass. It is, indeed, a remarkable fact that men of such varied races so widely spread should have thus selected as their food objects so little tempting in appearance, and so small and so inconspicuous as the seeds of grasses! Allied to the grasses are the sedges (forming the order _Cyperaceæ_), and the rushes (_Juncaceæ_). The apparently insignificant, but really interesting duckweeds (_Pistiaceæ_) should also be noted with the bullrushes (_Typheæ_), and the arums (_Aroideæ_). This last-mentioned order, familiar to us by the kind known as "Lords and Ladies," presents some climbing forms in tropical countries. Generally acrid, some species, when in flower, even produce headache and vomiting; at least an explorer was attacked with these symptoms after gathering forty specimens of _Arum dracunculus_. The order is also interesting from experiments as to vegetable heat, which have been made with the flowers of some of its species. The screw-pines (_Pandanaceæ_) are not "pines" at all, any more than "pine-apples" are pines. They are, indeed, trees or shrubs, which, from one point of view, may be regarded as gigantic bulrushes. The flowers of certain species are in some places eaten as the solid equivalent of a love potion. Allied to the plants of the last-mentioned order are the palms (_Palmaceæ_), which are the first really large trees we come to after leaving the tree-ferns and the gymnosperms. Amongst the more noteworthy palms may be mentioned the palmetto (_Chamærops_) of Southern Europe (a summer ornament of our public gardens), the date palm, the areca palm, the sago palm, the cocoa palm, the rattan palm--a natural cordage--and _Seaforthia_, so remarkable for its graceful and elegant form. Next may be enumerated the great order of lilies (_Liliaceæ_), to which the homely and useful onion, leek, garlic, chive, and asparagus belong, no less than a multitude of lovely flowers.