LECT. VII.] ANATOMY OP STEMS. 301 



enclosing vascular, ligneous cords, composed of 

 oblong cells like those on the circumference, sur- 

 rounding spiral and annular vessels. In the trans- 

 verse section the divided extremities of these cords 

 appear as clustered vascular spots in the cellular 

 substance *." 



The bark, if the surface of the stem can be 

 so named, of the more solid monocotyledons 

 is formed of the footstalks of the leaves; but 

 the real epidermis of both the ligneous and 

 herbaceous stems of this tribe, is always, as has 

 been already stated, so closely applied to the 

 part which it covers, as to be inseparable from 

 it by any means. Owing to this circumstance 

 it appears of a cellular structure, and its cha- 

 racter is regulated by the nature of the parts it 

 immediately encloses. In those plants, in which 

 it can be readily examined, it displays, under the 

 microscope, a regular series of organic exhaling 

 pores, each apparently surrounded by a glandu- 



* Vide Plate 5, fig. 8. A. B. C. A. represents the transverse 

 slice of a stem of Wheat, as seen through a good lens ; B. a 

 longitudinal section of the slice highly magnified ; a. the outer 

 cellular substance, composed of oblong cells and entire vessels ; 

 b. the interior cellular lining of the cylinder of the stem ; c. 

 a vascular bundle, consisting of a spiral vessel surrounded by 

 oblong cells ; C. a transverse section of the slice ; a. the tu- 

 bular cells immediately under the epidermis ; b. the common 

 cellular substance ; c. the vascular bundles. 



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