92 CORDAGE FIBRES 



Sisal hemp often shows an interlaced formation, with a pecu- 

 liar spiral thickening. The fibre elements are only about J in. 

 in length, and about T ^(j in. in diameter. They show a 

 remarkable broadening towards the middle. The width of the 

 lumen is frequently greater than that of the cell walls. The 

 ends are broad, blunt, and thick, but seldom forked. The 

 cross sections show no evidence of a median layer between 

 the elements. The sections are polygonal in outline, but 

 often have rounded edges, and the bundles are usually close 

 together. The lumen in the cross section is large and poly- 

 gonal in shape, though the edges of the lumen are more 

 rounded than those of the walls. 



Mauritius hemp, or aloe fibre, has fibre elements only 

 about -$ in. in length. Under the microscope it is hard to 

 distinguish it from Sanseviera fibre. The fibres are usually 

 cylindrical, and the cell walls thin and of uniform width. The 

 fibres show occasional fissure-like pores. The cross sections 

 are polygonal, with slightly rounded edges. In the Sanse- 

 viera fibre the lumen in the cross section is usually larger, 

 and the cell walls consequently thinner ; furthermore, the 

 lumen has a sharp- edged, polygonal form. 



In its microscopical characteristics Pita fibre is very similar 

 to Sisal hemp. 



Silk grass, or pineapple fibre, may be distinguished from 

 all other leaf fibres by the extreme fineness of its fibre 

 elements, which are about J in. in length. The lumen is 

 very narrow, and appears like a line. The cross sections are 

 polygonal in outline, and often flattened. The sections form 

 compact groups, which are often crescent-shaped, and are 

 enclosed in a thick medial layer of lignified tissue. 



Coir fibre possesses marked microscopical characteristics. 

 The fibre elements are short and stiff, being only about T Jo in. 

 in length, and T ^o^ in. in diameter. The cell walls are thick, 

 but rather irregularly so, in consequence of which the lumen 

 has an irregular outline. The points are blunt, and there are 

 a number of pores penetrating the cell wall. 



