MICROSCOPY OF PAPER. 99 



II. Fibres are short; less th^n diameter of field (Mag. =60). 

 (i) Ends of fibres frayed and torn. 



Cotton rag — Mechanical wood (conifers). 

 (2) Ends of fibres not torn. 



Coir — Elm — Willow. 

 Characteristic forms other than fibres are also present. - 

 I. Fibres are long; equal to or greater than diameter of field 

 (Mag. =60). 

 (i) Fibres quite broad in middle; tapering to point like a 

 bayonet, 

 (o) One or both ends of cells drawn out, sometimes 

 terminating in a tail. 

 Poplar — Birch — Porpor gum. 

 (6) Ends of cells cut off obliquely at blunt angle. 



Cottonwood — Whitewood — Black walnut — Holly 

 — Chestnut. 

 (2) Fibres not varying greatly in width, ends needle-like. 



(a) Characteristic forms (cells) large; covering i to ^ 



diameter of field. 

 Bamboo — Sorghum bagasse — Raffia — Tulip. 



(b) Characteristic forms small, cellular, serrated, or 



pointed. 

 Straw — Esparto — Sugar-cane bagasse — Live Oak. 

 II. Fibres are short; less than diameter of field (Mag. =60). 



(i) Cells comparatively long and narrow; quite sharply 

 pointed at one or both ends. 

 Magnolia — Tulip — Sweet buckeye. 



(2) Cells prismatic, stubby; ends blunt and cut off 



obliquely, 

 (o) Quantities of short, fine, transparent material with 

 square ends. 

 Holly — Chestnut. 

 (6) Field fairly clear except for fibres and characteristic 

 elements. 

 Pawpaw — Tree of heaven — Maple — Black 

 cherry — Willow. 



(3) Cells fragmentary, broken; fibres short. 



Groundwood — Elm. 



