258 RHIZOMES AND ROOTS. 



124) Salep. 



Salep consists of the enlarged roots of Orchis mascula, L. ; 

 0. militaris, L. ; 0. mono, L. ; and other species (N.O. 

 Orchidese). 



The root exhibits the following structure : 



(1) Epiblema } to which root-hairs are sometimes attached. 



(2) Cortex, which is very narrow. 



(3) Endodermis, of axially elongated cells with thin, wavy 

 walls. 



(4) Stele, traversed by a number of bundles. The parenchyma 

 of the stele consists of polygonal cells, most of which contain 

 starch that has been gelatinised by the boiling to which the 

 root is subjected ; some of the cells are much larger than the 

 others, and contain mucilage in which acicular crystals of 

 calcium oxalate are often embedded. 



The diagnostic characters of powdered salep are : 



(a) The abundance of mucilage. 



(b) The gelatinised starch. 



(c) The acicular crystals of calcium oxalate. 



