168 PEACTICAL BOTANY 



Here and there buds may be seen in the axils of the 

 scale-leaves, which repeat the characters of the main 

 bulb. 



The external details of the inflorescence may be 

 deferred for the present. 



II. Cut transverse sections of the scape : mount in 

 glycerine, and examine under a low power : observe that 

 the general arrangement is not unlike that in Zea. 



1. There is a superficial epidermis, of thick- walled 

 cells. 



2. A general ground-tissue, without sclerenchyma, 

 in which are embedded 



3. The vascular bundles ; these range themselves 

 as a more or less regular external series of smaller 

 bundles, and an internal series of larger bundles. 



Treat some sections with chlor-zinc- iodine, and exam- 

 ine under a high power : observe 



1. That the epidermis is a regular layer of cells, 

 with thickened and stratified outer and inner walls 

 consisting of cellulose (blue), clearly marked cuticle, 

 which is here found limiting the surface of both the 

 outer and inner walls : note stomata with two large 

 guard-cells. 



2. The ground-tissue consists of cells having thin 

 cellulose walls, and containing chlorophyll : it is divided 

 into an external cortex, and an internal mass, by an 

 irregular band of cells with a slight collenchymatous 

 thickening : this band runs externally to the outer 

 series of bundles. 



3. The vascular bundles are of the collateral type, 

 having the xylem directed to the centre of the stem, 

 and maintaining, though not very clearly, the form of the 



