12 PART I. ORGANOGRAPHY. 



curious Bottle-tree of Australia, the trunk is strongly bulged or 

 swollen in the middle; in the so-called stemless plants, like the 

 Dandelion, it is short and broad, forming scarcely more than a 

 point or thin disc, from which the roots shoot downward and the 

 leaves upward ; and in the Cactuses, succulent Euphorbias and 

 some other families of plants, it assumes a great variety of irreg- 

 ular or oddly grotesque forms. 



Direction of Growth. In this respect also there is great 

 diversity. The larger proportion of aerial or above-ground stems 

 are upright or erect, but some are ascending, that is, they rise 

 obliquely upward ; some are reclining, or at first erect, but after- 

 wards bending over as if too weak to stand ; some are decumbent, 

 or creeping along the ground, but with the apex ascending; some 

 are procumbent or prostrate, that is, lying wholly upon the ground, 

 and still others are repent, or creeping along the ground, rooting 

 as they grow 



Duration of Stems. There are wide differences in this 

 respect also. Some attain their full size in a few days, and in a 

 few days more completely disappear, while there are others that 

 possibly endure for a thousand years, and the vegetable world 

 presents almost every gradation between these two extremes. 



A stem which dies down to the ground at the close of the 

 season is called herbaceous ; an herb whose life terminates with 

 the season, or which springs from the seed, blossoms, ripens its 

 fruits, and dies completely all in the same season, is called an 

 annual ; if, however, the stem dies, but the underground parts 

 retain their vitality, and growth is continued another season, 

 during which the seeds are perfected, and it then dies completely, 

 it is called a biennial ; and if by underground parts the life of 

 the plant is continued indefinitely, through a period of years, it 

 is called a perennial. An aerial stem that is woody, freely 

 branching from near the ground, and of small size, not more 

 than two or three times the height of a man, is called shrubby or 

 fruticose ; if the stem is of a small size and woody only at the 

 base, it is described as an under-shrub or as suffruticose ; if the 

 stem is woody with a single trunk, and rises not higher than 

 twenty-five or thirty feet, it is called arborescent ; and if similar 

 to the last, but of larger size, rising to the height of thirty feet or 

 more, it is termed arboreous. 



