SUGGESTIONS Folt LAliO/UTOJlY WORK. 



V, 



gitudinal section) ami tlie smaller ones spiral 

 and annular. 



(2) Wedged in umong tlio vessels, the much 

 smaller tliick-Wiilled wood-cellp. These vc^ssels 

 and wood-cells toj?etlier constitute the xylum 

 portion of the fibro-vascular bundle. 



(3) A band of thin-walled, narrow and rather 

 rectangular cells, in regular radial rows, ihe 

 cambium. 1 



(4) External to the cambium, the bast, con- 

 sisting of many layers, the inner of thin-walled 

 cells and made up of siove-tubes an<l bast- 

 parenchyma, and llie outer of thiik-wallrd 

 cells constituting the bast-flbrea or scleron- 

 chyma. These elements external to the cambium 

 constitute the iihloem portion of the bundle. 



(d) The cortex, a band of several layers of chloro- 

 phyll-bearing cells surrouiuling the ring of fibro- 

 vascular bundles. The outer layers may show 

 cell-walls strongly thickened in the angles, 

 collenchyma {subcpkJerm is). 



(e) The medullary rayp. bands of i)arenchyma 



separating the fibro-vascular bundles and con- 

 necting the ]iith with the cortex. 



(f) The epidermis, a single layer of transparent 

 cells forming the boundary of the stem. 



Make drawinff.s- of fi.ssue.s observed. 



In a longitudinal radial section, follow the course of observa- 

 tion outlined above, noting all the tissues between the 

 pith and the epidermis, and making drawings. 



Compare a cross-section through a node with the cross-sec- 

 tion alreadj' observed. 



Stem of Maize. 



lu a cross-section o. an internode of a well-grown stem, ob- 

 serve the following tissues, commencing at the outside: - 



(a) The epidermis, a single layer of cells. 



(b) Immediately internal to (a) irregular groups of 

 sclerenchyma. 



(c) The groundwork of the section, consisting of 



thin-walled tissue (|)arenchymr.) in wliich are 

 imbedded 



(d) The separate fibro-vascular bundles, smaller 



and more numerous towards the outside than 

 towards the centre. 

 With a higher power, study the stnictur.- of a bundle and 



make out — 



(1) Four large openings (ves-scls). the two very large j 

 ones being pitted, and of the otlier two the one I 



