MAIZE. STEM. 107 



IV. From a young plant with leaves about three 

 inches long cut longitudinal sections, as above : mount 

 in water, and irrigate with solution of iodine. 

 Observe 



1. That in the neighbourhood of the surface of the 

 scutellum the starch grains are in course of demolition, 

 and that the central part of each is first attacked. 



2. That no starch grains are to be seen in the 

 epithelium of the scutellum. 



STEM. HERBACEOUS TYPE. 



I. Cut transverse sections of an internode of a 

 well-grown stem of Zea Mais ; mount in water. 



N.B. Fresh material may be used, but stems preserved in 

 alcohol are preferable. When fresh, the tissues are crowded with 

 air bubbles. The sections should be cut from the upper part of 

 one of the lower internodes, otherwise the vascular bundles may- 

 be found to be imperfectly developed. 



Examine with a low power, and, beginning the study 

 of the tissues at the periphery of the section, 

 observe 



a. A single layer of Epidermis, having the usual 

 characters : immediately below this are 



b. Irregular groups of Sclerenchyma with thick 

 lignified walls : internally lies 



c. A mass of Parenchyma, which forms the ground- 

 work of the whole section : embedded in this are 



d. Numerous Vascular bundles : note that they 

 are smaller, but more numerous near the periphery 

 than at the centre ; also that the position of the parts 

 of the bundles relatively to the centre of the section 

 is uniform. 



