LECT. VII.] ANATOMY OP STEMS. 293 



legists; and thence they have been regarded as 

 agamic. Many of them have no stem ; but among 

 those which possess it, in some it is solid, or 

 rather entire, in others hollow; and in the lat- 

 ter case, the cavity is often partially lined with 

 a very lax, dry, cellular web *. A conspicuous 

 root is rare; and, when it exists, consists of a 

 few small radical fibres only, composed of a 

 single thread, covered with a cribriform epider- 

 mis. Scarcely any facts are yet known respect- 

 ing the development and growth of this descrip- 

 tion of stem. 



ii. Stems which proceed from monocotyledonous 

 seeds are more complex in their structure than 

 the preceding. They are composed of two dis- 

 tinct parts, ligneous and cellular, which assuming 

 a determinate character, enable these stems to be 

 readily distinguished, even by the naked eye. 

 They comprehend both solid and tubular, or 

 entire and hollow stems ; and as there is some 

 difference in the arrangement of the parts in 

 these varieties, we shall examine them separately. 



* See Plate 5, fig. 1, which represents a longitudinal sec- 

 tion of the stem of Tall Agaric, Agaricus procerus ; a. the 

 stem ; b. its lax cellular lining, or pith, which in this example 

 nearly divides the hollow of the stem into two unequal cavi- 

 ties ; c. a fragment of the hat or pileus, to show the simplicity 

 of its union with the stem. 



u3 



