CHAPTER III. 



HISTOLOGY OF ANGIOSPEKM STEM, EOOT, 

 LEAF, AND FLOWER. 



99. Vegetable Marrow Stem (General Anatomy). 



Material for study may be obtained by raising Marrow 

 (or Cucumber) plants from seed in large pots or boxes of 

 soil ; when the plant is six to eight weeks old, turn it out 

 of the pot and place it entire in a large pan of boiling 

 water for three or four minutes. Then cut the stem 

 especially the lower part, starting from about 18 inches 

 below the apex into short lengths and place these in 

 alcohol. 



(a) Note that the stem is hollow, with (usually) five 

 ridges and furrows ; the bundles (usually ten) are in two 

 rings a smaller outer bundle to each ridge and a larger 

 inner bundle to each furrow. 



(6) Scrape the outer surface of the stem, so as to 

 remove part of the epidermis with its hairs ; note the soft 

 tissue which lies between the bundles the cells of this 

 ground tissue parenchyma can be seen with a lens. 



(c) After removing the epidermis, scrape away the soft 

 tissue below it, and note the shiny hard tissue (scleren- 

 chyma) which forms a wavy tube around the stem outside 

 of the bundles. 



(d) Slit a piece of stem by a longitudinal cut, and 

 isolate a strip of the sclerenchyma ; note that the strip is 

 very flexible, is easily split longitudinally, but is difficult 

 to break by pulling at the ends. 



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