. A manual of structural botany; an introductory textbook for students of science and pharmacy. Plant morphology. GLANDS 47 Retrograde Metamorphosis.—In all of these cases the change is from a more complex organ, or one of higher rank, to one of a lower, and is called Retrograde Metamorphosis, or Reversion of Type. Progressive Metamorphosis also occurs. It is seen in the gradual transformation of bracts, themselves transformed leaves, into sepals in the Barberry (Fig. 61), and of sepals into petals and petals into stamens. Even stamens may become metamorphosed into carpels or carpels into stam
. A manual of structural botany; an introductory textbook for students of science and pharmacy. Plant morphology. GLANDS 47 Retrograde Metamorphosis.—In all of these cases the change is from a more complex organ, or one of higher rank, to one of a lower, and is called Retrograde Metamorphosis, or Reversion of Type. Progressive Metamorphosis also occurs. It is seen in the gradual transformation of bracts, themselves transformed leaves, into sepals in the Barberry (Fig. 61), and of sepals into petals and petals into stamens. Even stamens may become metamorphosed into carpels or carpels into stamens, one instance being the flowers of the willow, where organs have been seen intermediate in appearance between the 62. Fig. 61. Structures from flower of Berberis, intermediate between petal and stamen. 62. Same from flower of Castalia. Teratology.—Cases of abnormal retrograde metamorphosis are very common, and have given rise to a separate department of study known as Teratology. Enation or Outgrowth.—Enation and the effects produced by if are well illustrated in one of their forms by the petals of certain genera of the Ranuneulaceae. The retention of a drop of nectar at the base of the petal of some species of buttercup is effected by the presence there of a minute scale (Fig. 63), covering over a slight depression. The nectar is partly lodged in this pit, partly held between the petal and the scale. In the Coptis (Fig. 64), a closely related plant, the depression is deepened into a more obvious cavity and the scale is dispensed with, while in the Delphinium (Fig. 65) the cavity becomes a long tube. Glands.—Although the detailed consideration of appendages will be taken up in connection with the several organs to which they apper-. 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 original Rusby, Hen
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