VEGETATIVE CELL TYPES IN SEED PLANTS
 
 
CELL TYPE
SUBCATEGORIES
LOCATION 
ORIGINATES FROM
FUNCTION
EXAMPLES
MERISTEMATIC = SELF PERPETUATING
1.  Apical meristem  
     A.  Single cell 
     B.  Multiple cells 
 		 1.  Shoot 
      A.  Terminal 
      B.  Lateral 
      C.  Adventitous 

2.  Root 
      A.  Terminal 
      B.  Lateral 
      C.  Adventitous

 1.  Tip (apex) of vegetative stems, developing inflorescences, and flowers 

2.   Beneath inner edge of root cap at tip (apex) of roots

 A. Initial terminal population are lineal descendents of cells of embryo 
B.  Subsequent lateral ones arise from existing shoot meristems or from pericycle of roots 
C.  Adventitious meristem cells arise from vascular cambium, pericycle, and cortex parenchyma
  • Self perpetuating
  • Formation of primary meristmatic tissue
 Coleus shoot apex 

Zea root apex
2.  Vascular cambial cell 1.  Fusiform Initials 

2.  Ray Initials

 Between secondary xylem and secondary phloem A.  Procambium of fascicular regions and from parenchyma of interfascicular regions in stems. 

B.  Procambium between xylem and phloem and periclycle outside xylem in roots.
  • Self perpetuating in tangential direction
  • Formation of secondary xylem in interior radial direction
  • Formation of secondary phloem in exterior radial direction
 Three year old twigs of 
     Tilia 
      Pinus 
 
 
3.  Cork cambial cell (Phellogen)
  • Between cork (phellem) and either phelloderm, cortex, or phloem tissue
  • Beneath surfaces exposed by abscission of leaves and stems and wounds
  • In stems, from either the epidermis, cortex, or phloem parenchyma cells
  • In roots, from the pericycle
  • Self perpetuating in tangential direction in some species; not in most
  • Formation of cork (phellem) in exterior radial direction
  • Formation of phelloderm in interior radial direction in some species
 Three year old twigs of 
     Tilia 
      Pinus 

Potato tuber
CELL TYPE SUBCATEGORIES LOCATION ORIGINATES FROM FUNCTION EXAMPLES
DERIVED EXCULSIVELY FROM PRIMARY MERISTEMS
4.  Cork 
(Phellem)		 Peripheral regions of stems, roots,  certain fruits, some bud scales, and petioles; often produced in response to wounds Cork cambium (Phellogen)
  • Restriction of gaseous exchange
  • Protection against disease vectors and fire
 Three year old twigs of 
     Tilia 
      Pinus 

Potato tuber
8.  Collenchyma Classified on basis of where the  thicker regions of primary cell wall are located within the cells Subepidermal layers or strands of stems, petioles,  larger veins of some leaves, and cortex of some roots. Ground meristem
  • Mechanical support of primary plant body
  • Photosynthesis
  • Carbohydrate storage
 Stems of 
     Solanum 
     Helianthus 

Rheum petiole
5.  Epidermal Outermost cell layer of foliar and floral organs; primary stems and roots Protoderm
  • Restriction of gaseous exchange
  • Protection against disease vectors
  • Storage of water and elaborated reserves
  • Absorption of water in roots and certain foliar structures
 Leaves of 
     Zea 
     Bryophyllum 
     Pinus
6.  Guard Cells Classified on basis of 
Geometric or 
Ontogenetic 
relationships with 
Subsidiary Cells		 Outermost cell layer of foliar and floral organs; primary stems Guard Cell Mother Cells of the protoderm which may also form some or all of the associated Subsidiary  
Cells
  • Regulation of gaseous exchange
 Leaves of 
     Zea 
     Bryophyllum 
     Pinus
13.  Transfer cell Classified on basis of location of wall ingrowths  in vascular tissue Primary xylem and phloem, pericycle of root nodules, stigmata of some flowers, secretory structures Procambium, protoderm
  • Transport of water, elements, and organic molecules over short distances where normal transport connections are not found
 Legume root nodule 

Anthocerus sporophyte/gametophyte 
 
CELL TYPE SUBCATEGORIES LOCATION ORIGINATES FROM FUNCTION EXAMPLES
DERIVED FROM BOTH PRIMARY AND SECONDARY MERISTEMS
7.  Parenchyma Classified on basis of function or position in the plant body Most all plant organs Ground meristem, procambium, vascular cambium, and cork cambium
  • Dedifferentiation to form interfascicular cambium and adventitious shoots and roots
  • Hydrostatic support of primary plant body
  • Photosynthesis
  • Storage of water and elaborated reserves
  • Secretion and excretion of various substances
  • Formation of callus in response to wounding
 Three year old twigs of 
     Tilia 
      Pinus 

Potato tuber 

Leaves of 
     Zea 
     Bryophyllum 
     Pinus
8.  Collenchyma Classified on basis of where the  thicker regions of primary cell wall are located within the cells Subepidermal layers or strands of stems, petioles,  larger veins of some leaves, and cortex of some roots. Ground meristem
  • Mechanical support of primary plant body
  • Photosynthesis
  • Carbohydrate storage
 Stems of 
     Solanum 
     Helianthus 

Rheum petiole
9.  Sclereid Classified on basis of cell geometry Outer layer of seeds and some fruits; diffusely distributed in pith, cortex, phloem, outer bark,  and  leaf mesophyll Protoderm, ground meristem, procambium, vascular cambium, and phellogen.  
Also from sclerosis of parenchyma cells.
  • Protection of embryos and seeds
  • Mechanical support
 Pyrus fruit 
Phaseolus seed 
Camellia petiole 
Leaves of  
     Nymphaea  
    Osmanthus  
    Olea 
10.  Fiber 1.  Bast (Phloem) 
2.  Libriform (Xylem) 
3.  Fiber-tracheid		 Cortex, vascular tissues of stems and roots,  as strands or sheaths of leaf veins, epidermis of some leaves Protoderm, ground meristem, procambium, and vascular cambium
  • Mechanical support
 Leaves of  
     Zea 
     Helianthus 

Twigs of 
     Tilia 
     Fraxinus
11.  Tracheid 1.  Vascular 
2.  Vasicentric		 Xylem, transfusion tissue of gymnosperm leaves Procambium, vascular cambium
  • Transport of water, elements, and some phytohormones
  • Mechanical support
 Twigs of  
     Quercus 
     Pinus
12  Vessel member or element Xylem Procambium, vascular cambium
  • Transport of water, elements, and some phytohormones
  • Mechanical support
 Twigs of  
     Quercus 
     Magnolia
13.  Transfer cell Classified on basis of location of wall ingrowths  in vascular tissue Primary xylem and phloem, pericycle of root nodules, stigmata of some flowers, secretory structures Procambium, protoderm
  • Transport of water, elements, and organic molecules over short distances where normal transport connections are not found
 Legume root nodule 

Anthocerus sporophyte/gametophyte 
 
14.  Sieve cell Gymnosperm Phloem Procambium, vascular cambium
  • Transport of photosynthate
 Twigs of 
     Pinus 
     Thuja
15.  Sieve-tube member or element Angiosperm Phloem Procambium, vascular cambium
  • Transport of photosynthate
 Cucurbita stem 
Liriodendron twig
16.  Laticifers Classified on basis of presence or absence of 
     A.  Anastomoses 
     B.  Articulations 
 		 Pith, xylem rays, phloem, cortex, leaf mesophyll Ground meristem, procambium, and vascular cambium
  • Secretion and storage of latex
 Leaves of 
     Allium 
     Lactuca 
     Asclepias 
     Ficus 
Stems of 
     Ficus 
     Cannabis