76 



BOTANY. 



specimens may be transferred to a glass slide and dissected by tapping 

 gently upon the centre of the cover-glass. 



103. Laticiferous Tissue. In many orders of Phanero- 

 gams tissues are found whose component elements contain a 

 milky or colored fluid the latex. To these, although vary- 

 ing greatly in structure and position, the general name of 

 Laticiferous tissues has been given. For the sake of simpli- 

 city two general forms may 

 be distinguished : (1) that 

 composed of simple or branch- 

 ing dements (Fig. 64), which 

 are scattered through the 

 other tissues. As found in 

 EuphorMacece, where they oc- 

 cur in parenchyma, they are 

 somewhat simply branched, 

 and have very thick walls 

 (Fig. 64, B) ; in other orders 

 they are thin walled and are 

 sometimes inclined to anasto- 

 mose. From their position it 

 is quite certain that the ele- 

 ments of this form of laticif- 

 erous tissue frequently replace 

 bast fibres. In such cases 

 they are said to be metamor- 



Fig. 66 Laticiferous cells of the onion, > 



from a longitudinal section of a scale of pllOSCd DilSt Ilbres , 111 Other 

 the bulb, e, epidermis with cuticle c ; w, , , , 



parenchyma ; sg, coagulated contents of CaSCS, however, they appear 

 faticiferous cells, contracted eo as to show i i ~f l..,' a , v.,,4- 



the porous walls ; q, q, transverse wall. not tO DC OI tlllS natuie, DUt 



After Sachs. ^ o ar j se f rom the parenchyma 



by the absorption of the horizontal partition- walls, f 



* There is an objection to the word metamorphosed in this connec- 

 tion, as it does not exactly express the relation between the laticiferous 

 elements and the bast fibres. It must not be understood that the 

 former are made by a transformation of the formed bast fibres ; the 

 relation is rather that they develop from what under other circum- 

 stances would have developed into bast fibres. We may express the 

 relation by saying that laticiferous elements and bast fibres are closely 

 related sister elements. 



t " According to Hanstein, it is probable that in some Aroideae vessels 



