PLANT STUDIES 



PART IV, STEMS 



The budding twigs spread out their fan 



To catch the breezy air ; 

 And I must think, do all I can, 



That there was pleasure there. 



WOBDSWORTH. 



The service ordinary stems do for 

 plants is the production of leaves, roots, 

 and the flowers which are most important 

 to the plant, since they, in turn, produce 

 the seeds. Stems are also the canals 

 which carj-y the material made by the 

 leaves into every part of the plant and 

 bring up from the roots the nourishment 

 gathered out of the earth. 



The stems that we think most about 

 live above ground. Many of them, when 

 the winter comes, die down completely, 

 and the particular plant of which they 

 formed a part never appears again, 

 though others like it grow the next year 

 from the seed. Such plants are herba 

 ceous, that is, live herbs, such as butter 

 cups, anemones, columbines, and lark 

 spurs. Other stems, less soft and deli 

 cate than those of herbs and able to live 

 from year to year without dying when 

 winter comes belong to shrubs and trees. 

 The hardy lilac and syringa have woody 

 stems, while those of the oak and ash are 

 still tougher and stronger. 



Stems are not all erect but hold them 

 selves in different ways : The white 

 clover creeps ; peas, grapevines, and ivy 

 climb ; and the morning glory twines. 

 To suit its particular purpose the plant 

 modifies certain branches. Tendrils are 

 slender branches which grow out from 

 the stem until they reach something 

 about which to cling, then twist spirally, 

 so become shorter, and the vine is drawn 

 nearer the support. The Virginia creep 

 er has another plan by which it is enabled 

 to climb a wall or cliff. The ends' of the 

 tendrils are flattened into disks which 

 adhere so closely to the smooth surface 

 that the vine is able to cling to it and 

 so ascend. 



Another kind of stem important to 

 plants, besides those that grow above 



ground, is that which grows below it. 

 These underground stems are not pos 

 sessed by all plants, for we have already 

 seen that many plants are entirely killed 

 by cold weather. But some plants store 

 up nourishment in a portion of the stem, 

 either partly or wholly covered by earth, 

 so that they are able to live year in and 

 year out. A rootstock is a thickened 

 stem which provides foods for its buds 

 just as the thickened cotyledons did for 

 the young embryo. The mint has a root- 

 stock that creeps along underneath the 

 ground, at intervals sending up stems 

 to the air, which produce leaves and 

 seeds and then in the fall die down. But 

 the underground stem, the rootstock, 

 lives on, ready to repeat the process of 

 producing a new plant the following- 

 spring. Such plants are hard to get rid 

 of, those that grow "by the root," as it 

 is said ; but we know it is by the stem 

 they grow since only stems produce buds 

 and leaves, or in the case of the root- 

 stock, scales which correspond to leaves. 

 - If one cuts down the usual weed and 

 destroys the root, the plant may be killed 

 completely. But cut through the stem 

 of mint or calamus and you have two 

 plants instead of one; for each part of 

 the rootstock is able to produce roots and 

 send up stems or leaves. 



Some rootstocks are curiously marked. 

 Solomon's seal is so called from the fact 

 that it bears on its surface scars that re 

 semble the impression of a seal. Each 

 year at the end of the rootstock a bud is 

 formed which in the spring develops into 

 the plant above ground. In the fall this 

 plant dies and breaks off from the root- 

 stock leaving a scar. Again a bud is 

 formed on the rootstock at the end of the 

 year's growth, ready to develop the fol 

 lowing spring. So at regular intervals 



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