GLOSSARY 4 



Cell. --A chamber or compartment at some time containing a protoplast; cells form the struc- 

 tural units of plant tissues. 



Fibre, Fiber (Am.). --A general term of convenience in wood anatomy for any long, narrow 



cell of wood or bast other than vessels and parenchyma. Note: Often further qualified 

 as wood fibres or bast fibres; the former including both the tracheids of gymnosperms 

 and the libriform wood fibres and fibre -tracheids of woody angiosperms. Also used 

 loosely for wood elements in general. 



Growth layer. --A layer of wood or bark produced apparently during one growing period; fre- 

 quently, especially in woods of the temperate zones, divisible into early and late wood 

 or bark (IAWA). 



Parenchyma. - -Tissue composed of cells that are typically brick -shaped or isodiametric and 



have simple pits; formed in wood from (a) fusiform cambial initials by later transverse 

 divisions of the daughter cells (axial parenchyma), or (b) ray initials (ray or radial 

 parenchyma). Syn. Soft tissue, Storage tissue . See also Parenchyma cell, fusiform. 

 Note: Primarily concerned with the storage and distribution of food materials. Termed 

 wood parenchyma or xylem parenchyma if occurring in the xylem, and phloem paren- 

 chyma if in the phloem . 



Parenchyma, apotracheal. - -Axial parenchyma typically independent of the pores or vessels. 

 Note: This includes Terminal, Diffuse, and Banded apotracheal parenchyma. 



Parenchyma, axial .- -Parenchyma cells derived from fusiform cambial initials . Syn. Longi- 

 tudinal parenchyma (deprec .), Vertical parenchyma (deprec .), cf. Parenchyma, ray. 



Parenchyma, diffuse. - -Single apotracheal parenchyma strands or cells distributed irregularly 

 among fibres, as seen in cross section (IAWA modif.). 



Parenchyma, paratracheal . - -Axial parenchyma associated with the vessels or vascular tra- 

 cheids (IAWA modif .) . Note: This includes Scanty paratracheal, Vasicentric, Aliform 

 and Confluent parenchyma. 



Parenchyma, ray. --Parenchyma composing the rays wholly or in part. (IAWA modif .) . Syn. 

 Radial parenchyma. 



Parenchyma, terminal. - -Apotracheal parenchyma cells occurring either singly or forming a 

 more or less continuous layer of variable width at the close of a season's growth. 

 Note: Before a distinction was made between "terminal" and "initial" parenchyma, 

 this term was used to include both forms and is still used in this sense as a term of 

 convenience . 



Perforation, simple. --A single and usually large and more or less rounded opening in the per- 

 foration plate, cf. Perforation, multiple (IAWA) . 



' Excerpts from Committee on Nomenclature, International Association of Wood Anato- 

 mists. International Glossary of Terms Used in Wood Anatomy. 1957, 



69 



