18 



BOTANY. 



and flowering plants, and give strength and hardness to 

 their stems and leaves. 



42. Two varieties of fibrous tissue may be distinguished, 

 viz., (1) Bast (Fig. 10, B), and (2) Wood (Fig. 10, A). The 

 fibres of the former are usually thicker walled, more flexi- 

 ble, and of greater length than those of the latter. In both 

 forms the fibres are sometimes observed to be partitioned. 



Fig. 10.— .4, wood-fibres of Silver Maple isolated by Schulze's maceration; B, 

 bast-flbres; 6, 6, portions of fibres more highly magnified. 



43. Milk Tissue {Laticiferoits Tissue). — ^In many orders 

 of flowering plants tissues are found which contain a milky 

 or colored fluid — the latex. For the sake of simplicity two 

 general forms may be distinguished: (1) that composed of 

 simple or branching tubes (Fig. 11), which are scattered 

 through the other tissues. As found in the Spurge family, 

 they are somewhat simply branched and have very thick 



