Objects for the Microscope. 29 



CHAPTER II. 



SECTIONS OF WOOD. 



THE use of these sections is to show the structure of the 

 stem of plants, and the difference between the two great 

 divisions of the vegetable world into endogens and exogens. 

 An endogen is a plant which has long straight-veined leaves 

 like a Palm, a Cane, a Lily, Iris, Daffodil, and all the 

 grasses. The flowers are usually divided into three, or a 

 multiple of three ; the embryo has only one seed-lobe, or 

 cotyledon, and the stem is like the section of 



RUSCUS, 



or Butcher's-broom, a common shrub in waste and watery 

 places, with very rigid dark-green leaves, tipped by a sharp 

 spine : it blossoms in April, but is chiefly admired for its 

 large scarlet autumn berries, one in the axil of each leaf. 

 This pretty section apparently a fine lace-pattern shows 

 the structure of an endogenous tree; it grows from within, 

 and is composed of a dense mass of simple cells, in the 

 midst of which, in varied patterns, run upwards bundles of 

 denser cells called " fibro-vascular" ; and each bundle has 

 one or more ducts, best seen perhaps in a section of 



WANGHAE CASE. 



Sometimes the centre cells disappear and leave the stem 

 hollow, as in the grasses and many of the water plants. 

 Compare now this slide, and also a section of 



ASPARAGUS, 



with that of the Hazel or Apple. 



SECTION OF HAZEL. 



Here we see very distinct organization on quite a different 

 plan. The exogen has veined and reticulated leaves ; the 



