Fruits may be classified as dry and fleshy

The former may be dehiscent (capsule, silique, silicle, legume, follicle and pyxis), or indehiscent (achene, caryopsis, samara and nut). The dehiscent forms are usually many-seeded, the indehiscent one seeded. Fleshy fruits include the pome, drupe, berry and pepo. To many seeds are attached feathery, cottony or wing-like appendages, to a ist in distribution by the wind, or prickles and hooked spines to aid in distribution by animals. In the distribution of plants over the earth numerous floral regions may be distinguished. The marine flora is mainly of Algæ ; the fresh water, of Algæ , a few flowerle plants and the aquatic flowering plants; the terrestrial of Fungi , and the most of the higher Cryptogams and flowering plants. In the tropics the vegetation is most luxuriant; in temperate regions le so, but in general more robust; in the frigid zones only the most hardy plants can exist. Through three corresponding regions we may also pa altitudinally from sea-coast to mountain-top. There are also great forest regions, as those of northern and eastern America and northern Europe and Asia; great arid regions whose vegetation is dwarfed and scanty, as those of northern Africa, central Asia and our own Great Interior Basin: and great prairie regions, inhabited by gra es and other campestral forms, of which our western prairies, the pampas of S. America and the steppes of Asia are examples. But similar regions, while having floras similar in kind, usually differ widely in the species and even in the genera represented. There are, however, frequent examples of widely separated regions with floras unusually similar. and for explanation of these cases we must go back to the history of ancient geographical distribution in the records of Paleobotany.