. A compendium of general botany. Plants. of the primary axis turns from the median line and develops a sec- ondary branch or axis; the secondary axis takes the direction of growth of the primary axis, and finally divides again, forming an axis of the third order; this third axis bears the same relation to the second axis as the second axis bears to the first, and so on. This forms what is known as a "sympodium " or pseudo- axis. The rhizome of Polygonatum multifiorxim is a good example (Fig. 106). The expression sympodium implies that the organ is composed of different^wZ««, that is
. A compendium of general botany. Plants. of the primary axis turns from the median line and develops a sec- ondary branch or axis; the secondary axis takes the direction of growth of the primary axis, and finally divides again, forming an axis of the third order; this third axis bears the same relation to the second axis as the second axis bears to the first, and so on. This forms what is known as a "sympodium " or pseudo- axis. The rhizome of Polygonatum multifiorxim is a good example (Fig. 106). The expression sympodium implies that the organ is composed of different^wZ««, that is of shoots or branches of different orders. Two organ systems may be exactly alike in the beginning but may by wholly different in'the mature state. This statement is contradictory to what was said at the beginning of this chapter. It can readily be supposed, and it is actually true that a spike and an umbel are alike at the beginning of their formation. The attempt to co-ordinate development and the mature state is liable to cause confusion. One must either trace the mature state back along the line of its devel- opment or mce versa^ in order to have a correct understanding of the true conditions. To trace the development of an organ-system is not always an easy task. An example, which incidentally introduces us to a very diflScult chapter of morphology, will show that under certain con- FiG. 106.—Rhizome of Poly- gonatum multiflorum. a. Bud ; b, basal portion of stem ; c and d, stem-scars. (After Krass and Landois.). Fig. 107. (Diagramatic.) Fig. 108. (Diagramatic.) ditions it is impossible to judge of the course of development from a study of the mature state. Very frequently there are deviations from the normal axillary branching. This I will attempt to explain. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the origin
Size: 2637px × 948px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectplants, bookyear1896
