82 LEAVES. 



(45) Savin. 



The young twigs of Juniperus Sabina, Linn. (N.O. Coniferse). 



The young twigs of savin are <3dDBely covered with minute thick, 

 imbricated, opposite leaves, which are appressed and frequently 

 adnate to the stem for a considerable portion of their length on 

 the dorsal surface of each leaf a large depression (oil-gland) may be 

 observed. 



The transverse section of the leaf is nearly semicircular in outline 

 and exhibits a centric structure. The cells of the epidermis are 

 nearly square in section and provided with a thick cuticle. In 

 surface view they have pitted walls, and in the lateral portions of 

 the leaf are nearly isodiametric, whereas in the central they are 

 axially elongated. Stomata occur only in the lateral portions, and 

 are characterised by the little recurved projections at each extremity, 

 as well as by being lignified. 



Below the epidermis there is a hypoderma of thickened more or 

 less lignified fibres. 



The mesophyll consists of polygonal, rounded or elongated cells ; 

 near the dorsal surface there is a large oil-gland. The wood of the 

 midrib is composed of tracheids, and below it is the bast, the cells 

 of which are arranged in the regular rows characteristic of coniferous 

 plants. On each side of the midrib there may be observed a group 

 of lignified cells with areolated pits. 



The diagnostic characters of powdered savin are : 



(a) The characteristic stomata which even in younq leaves are 

 lignified. 



(b) The epidermis with fibrous hypoderma, the latter not always 

 easily seen. 



(c) The lignified cells with areolated pits. 



NOTE. The thickened lignified cells, sc, shown in the illustration, 

 are characteristic of J. phcenicea, Linn., which is often sold in 

 France in powder in the place of J. Sabina. 



