296 ON THE PROGRESSIVE DEVELOPMENT OF 



Lofty One, who sitteth upon the circle of the Heavens and in- 

 habiteth Eternity. 



The various species of the fern tribe, those leafy expansions, 

 some of while rival even the mosses in elegance of form and 

 delicacy of structure, while others vie with the loftiest denizens of 

 the tropical forests, are among those forms of vegetation, in the 

 internal texture of which tubes or vessels, as well as cells, are 

 found to exist. They constflute, as it were, the transition link 

 between the cellular and vascular plants, being allied to the 

 latter in internal structure, while in external configuration, and 

 more especially in their fructification, they are intimately con- 

 nected with the former. In that covering of herbage, the verdure 

 and freshness of which gives such a charm to the rich scenery 

 of the valleys and plains of our native country, we find many 

 different species of plants. These are called gramina or grasses, 

 and resemble each other very closely in their general structure 

 and appearance, constituting one of the most natural groups 

 with which we are acquainted. They have for the most part 

 fibrous roots, a tubular jointed stem, narrow ribbed leaves, and 

 an elongated spike or panicle of flowers, in all which parts, 

 whether root, stem, leaves, or flowers, we find the cellular 

 structure to be combined with the vascular, — vessels or tubes 

 traversing in a longitudinal direction the general cellular texture 

 of the plant. The same combination of vascular and cellular 

 structure is found in the sedges and rushes — in the numerous 

 species of iris — in the lilies — the Orchideof, and others, con- 

 stituting the first division of the flowering plants. To trace the 

 connections between the several families of the Vasculares, or to 

 examine the gradations by which they insensibly pass into each 

 other, is not necessary for our present purpose, since in these 

 more complex and highly organized forms of vegetation there is 

 a unity of structure prevailing, with certain modifications, 

 throughout the whole. It will be sufficient if we examine the 

 several parts or organs of which these plants consist separately 

 and in detail, pointing out as we proceed the modifications in the 

 development of these several parts as they occur in plants of a 

 higher or lower degree of organization. 



The more important divisions of the vegetable organization, 

 as it exists in the more highly developed families of plants, are 

 the root — the stem and branches — the leaves — the flowers — the 

 fruit, including the seed — and lastly, bulbs and buds. 



The external characters of the root vary considerably. 

 In grasses, as we have just observed, it is generally fibrous, 

 sometimes creeping, rarely bulbous; whereas, in many others 

 of the monocotyledonous plants, the tulip for instance, it is bulb- 

 bous. In every true root, however, a fibrous portion will be found 

 to exist, and it is the ultimate fibrils or divisions of the fibrous 

 part of the root, with the minute vesicular bodies at their extremi- 

 ties, which constitute the essential port of this organ. It is by 



