136 



PLANT ANATOMY 



Fi^. 47.— Cross section of leaf of DiKitalis purpurea, phowing finer anatomy of conducting vessels 

 also hairs and glands. (Tschircli). 



the pro^onco or absence of the palisade 

 colls are of great importance, (a) 



3. THE RESPIRATORY TISSUES 

 are those which enable the plant to take 



and watery vapor. They are the tissues 

 of gaseous exchange. They occur in the 

 epiderniis of leaves as the Stomata and 

 as Water Pores, and in the epidermis 



Fiff. 48.— Cross section of Melaleuca minor showing e. Epidermis, p. Palisade cells, sp. Stomata. fc. 

 stone cells. c«. oil reservoirs, (01. Cajeput), g. vessel portion (xylem)-^. sieve portion (Phloem), wltb 

 h. bast fibres of the same. (Tschirch). 



in food from the atmosphere in the form 



of carbon dioxide and to give off oxygen 



(a) Meyer, Officlelle Blatte und Kraiiter, 

 Halle, 1882. Lemaire, Determination hls- 

 tulogique des feoilles medieinales. Paris, 



m T. y^^^', -^^^^^ ^^r Pharmacognosie. 

 Tschirch und Oerstele, Atlas der Pharnia- 

 cognosie. Moeller, Microskopie. 



of stems as Stomata and Lenticels. As 

 a part of the respiratory tissues Inter- 

 cellular Spaces should be borne in mind, 

 as they provide moans of commuuicatiou 

 between the internal tissues and the 

 stomata and lenticels. 

 The Stomata are peculiar modifications 



