PLANT TISSUES 
IOI 
PARENCHYMA 
Parenchyma or Fundamental Tissue is the soft tissue of plants, 
consisting of cells about equal in length, breadth and thickness 
(isodiametric) with thin cellulose cell walls enclosing protoplasm and 
a nucleus and frequently substances of a non-protoplasmic nature. 
There are four generally recognized types of parenchyma, viz.: 
Ordinary Parenchyma (Soft Ground Tissue, Fundamental Tis¬ 
sue). —Next to the meristem this is the least modified of all plant 
tissues. It is generally composed of thin-walled cells, commonly 
polyhedral or spheroidal in form and often of approxinately the 
same length, breadth, and thickness (isodiametric), the cell walls are 
composed of cellulose which is usually unmodified. Occasionally 
the outline of the cells is star-shaped, as in the Wood Rush or Pick¬ 
erel Weed or the cells may be several times as long as wide, as in 
Pelargonium, etc. Moreover, markings may occur on the walls. 
These may be of the nature of pores, as in the parenchyma cells of 
the pith of the Elder or Sassafras, annular or reticulate thickenings, 
as in the Mistletoe, or spiral thickenings, as in certain Orchids. 
Protoplasm and a nucleus are always present, but in old cells are 
only seen as a thin layer pushed up against the cell wall. Ordinary 
Parenchyma may be seen composing the soft tissues of roots, stems, 
and barks. 
Assimilation Parenchyma (Chlorophyll or Chromophyll Paren¬ 
chyma, Chlorenchyma)* —This form of parenchyma tissue is found 
in foliage leaves, floral leaves, in the outer region of young green 
stems and fruits. Its cells are thin walled and vary in shape from 
more or less isodiametric to irregular and elongated forms. The 
cells always contain chloroplasts or plastids, in whose pores may be 
found some other coloring substance. 
Conducting Parenchyma. —This type of parenchyma functions 
in the rapid translocation of food materials to distant regions in the 
plant. It includes the wood parenchyma cells of the xylem which 
convey a portion of the crude sap (water with mineral salts in 
solution) and the phloem parenchyma (soft bast) which transports 
the elaborated sap (carbohydrate and proteid material in solution). 
Conducting parenchyma cells differ from those of ordinary paren- 
