44 



STEMS. 



[section 6. 



sort, like tliose of the Solomon's Scul (Fit^. 09), which gave this name to 

 the plaut, I'rom their looking somewhat like the impression ot'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 tlie 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. 



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 cer- 

 tain step, with only a narrow interval. In vigoi'ous 

 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. 



109. An upright or short rootstock, like this of Trillium, is commonly 

 called a C.'VUDex (93) ; or when more shortened and thickened it would 

 become a corm. 



110. A Tuber may be understood to be a portion of a rootstock thick- 

 ened, and with buds (eyes) on tiie sides. Of course, there are all grada- 

 tions between a tuber and a rootstock. Helianthus tuberosus, the so-called 

 Jerusalem Artichoke (Fig. 101), and the common Potato, are typical and 

 familiar examples of the tuber. The stalks by which the tubers are at- 

 tached to the parent stem are at once seen to be different from the roots, 

 both in appearance and manner of growth. The scales on the tubers are the 

 rudiments of leaves ; the eyes are the buds in their axils. The Potato-plant 



Fig. 99. Rootstock of Solomon's Seal, with the bottom of the stalk of the sea- 

 son, and the Inul for the ne.xt year'.s growth. 



Fig. 100. The very short rootstock and strong terminal bud of a Trillium or 

 Birthroot. 



