BOTANICAL SUBJECTS. 



299 



XV.— OIL GLANDS, COI^CEPTACLES, AXD FIGS. 



Oil Glands and Conceptacles. 



Le Maout and Decai.*<iie, in their " System of Botany," 

 p. 140 (1873), evidently had considered oil glands as ordinary 

 glands, for they say, " Sometimes the glands are sunk in the 

 thickness of the bark, but they are always near the epidermis ; 

 such are the jjlands called vesicular of the leaves of St. John*s 

 Wort, and Myrtle, and of the bark of the Orange, Avhich contain a 

 volatile oil." , 



According to Strasburger and Hillhouse (1889) the oil glands 

 of Ruta^ Graveolens, and Dictamuns Fraxinella are first cellular, 

 then the cells break down, and are converted into essential oil, 

 the breaking down commencing at the centre, as shown in 

 Fig. 127 (a) and 128 (6). At p. 164 they say, " The oil gland 



Fig. 127. Oil glands, or cavities of Ruta Graveolens (Strasburger and 

 Hillhouse) : (a) drop of oil. 



is lysegeuovs in origin, that is, it arises from the breaking down 

 of cells, instead of from their separation. This breaking down 

 commences at the centre of the mass of gland cells." 



