Some Mexican Fiber Plants. 



29 



The number of fibers in the leaf varies greatly in these 

 plants. A section of a mature leaf of lechuguilla showed 150 

 fibers more or less visible to the unaided eye. In a Yucca leaf 

 5.5 mm. in diameter and 33 mm. wide, a part of the section 5 mm. 

 square showed 150 fibers, and a like area in a section of a young 

 leaf of the maguey, 7 mm. thick and 60 mm. wide about 50 

 fibers were visible. Thus it is evident that a lechuguilla leaf 

 may possess about 150 fibers, that of the palma 600 more or less, 

 and of the maguey 300 up. This enumeration includes the finer 

 fibers which are mostly lost in the process of extraction so that 

 probably less than one-third can be counted on as the yield 

 from the leaves of the Agaves, though possibly more than that 

 may be realized from the Yucca. 



The fibers extend direct from base to tip of the leaf in 

 each case, and as stated above, in association with the vascular 

 bundles. There are usually two strands with each bundle, one 

 with the xylem the other with the phloem. As a rule the 

 heavier mass of the sclerenchyma is on the side of the bundle 

 nearest the surface of the leaf. These different fibers have 

 characteristic form and structure as they appear in section. 

 Those of lechuguilla near the surface of the leaf are round, semi- 

 circular or crescentic in the central part, and associated with the 

 phloem, but a much more slender sclerified strand and one which 

 might easily be overlooked is on the opposite side of the bundle 

 in contact with the xylem. In the maguey, as in lechuguilla 

 the heavier strands are in contact with the phloem and toward 

 the surface of the leaf, but a well developed, though thinner 

 mass, forms an angle in which the xylem is situated. In the 

 palma the sclerenchyma strands are likewise doubled, but in 

 this case the heavier fiber is on the side of the bundle toward 

 the center of the leaf associated with the xylem and on the 

 opposite side of those bundles nearer the surface, and there 

 with the phloem. In all three cases the heavier mechanical 

 strands are, in the bundles near the surface, associated with 

 the phloem, both on the upper and lower sides of the leaf, the 

 orientation of the bundles being reversed, showing xylem upper- 

 most in those bundles near the lower side of the leaf and the 

 phloem uppermost in those nearer the upper side. 



In the oldest leaves the fibrous tissue becomes very strongly 

 developed and in some cases too coarse for use. The youngest 



