BAST-FIBRES. 



89 



and possesses the power of swelling in water and in dilute acids 

 (compare Collenchyma) ; in sonic others the outer part of the wall 

 is gelatinous, while the inner is hard. Morus alba, Gleditschia 

 triacanthos, and Robinia Pseudaeacia are examples of the first, 

 Astragalus falcatus of the second, condition (Sanio). 



277. One of the most striking characters of the bast-fibres of 

 many plants is the abundance of crystals found therein. Ex- 

 cellent examples are afforded by the inner bark of some of our 

 ligneous plants (294). 



278. The firm attachment of fibres to those above and those 

 below them has given rise to erroneous ideas relative to the 

 length of single fibres, as the table on the following page shows. 1 



By careful management it is possible to isolate a connected 

 thread of fibres of great length ; the value of fibres for textile 

 purposes depends largely upon this fact. 



1 The table on page 90 has been compiled from data given by Wiesncr and 

 also by Vetillart, which are here rearranged for greater convenience of refer- 

 ence. 



Fio. 66. Fibre of Agave Americana : a and b, *f ; c, *f . Only the upper part of 

 each fibre is shown in the left-hand figures. The right-hand figure shows a cross-section 

 of a group of cells. 



FIG. 67. Fibre of Coir (Cocos nucifera) : a and c, f ; b, f . a shows three separate 

 and complete fibres, b, the upper part of a single one, c, a cross-section of a group of 

 cells. 



Fio. 68. Transverse section through leaf of Camellia (Thea) viridis, showing: 

 a, epidermis; b, branched liber-cell; d, oil-drop; e, crystals. (Mirbel.) 



