107. Some rootstocks are marked with large round scars of a different sort, like those of the Solomon's Seal (Fig. 99), which gave this name to the plant, from their looking somewhat like the impression of a seal upon wax. Here the rootstock sends up every spring an herbaceous stalk or stem, which bears the foliage and flowers, and dies in autumn. The _seal_ is the circular scar left by the death and separation of the base of the stout stalk from the living rootstock. As but one of these is formed each year, they mark the limits of a year's growth. The bud at the end of the rootstock in the figure (which was taken in summer) will grow the next spring into the stalk of the season, which, dying in autumn, will leave a similar scar, while another bud will be formed farther on, crowning the ever-advancing summit or growing end of the stem. [Illustration: Fig. 99. Rootstock of Solomon's Seal, with the bottom of the stalk of the season, and the bud for the next year's growth.] 108. As each year's growth of stem makes its own roots, it soon becomes independent of the older parts. And after a certain age, a portion annually dies off behind, about as fast as it increases at the growing end, death following life with equal and certain step, with only a narrow interval. In vigorous plants of Solomon's Seal or Iris, the living rootstock is several inches or a foot in length; while in the short rootstock of Trillium or Birthroot (Fig. 100) life is reduced to a narrower span. [Illustration: Fig. 100. The very short rootstock and strong terminal bud of a Trillium or Birthroot.] 109. An upright or short rootstock, like this of Trillium, is commonly called a CAUDEX (93); or when more shortened and thickened it would become a corm.