DENDROLOGY WOOD ANATOMY LAB III


I.  The first part of this exercise will acquaint you with fundamental anatomical features of
gymnosperm wood. You may wish to review these features on your own - feel free to do so.  The
numbers in (parentheses) following each feature below refers to the slide number in the box
labeled Gymnosperm Wood Demos.  The numbers in [brackets] refer to the specimen numbers in
the wood identification collection.  You will find the on-line help in the Gymnosperm Wood
component of the MUDES of use during this exercise.

PLEASE RETURN ALL SLIDES TO THEIR APPROPRIATE SLOTS WHEN YOU ARE
DONE VIEWING THEM. 

Specific objectives for you to strive to master include:  a)  What section (transverse X, radial
longitudinal R, or tangential longitudinal T) is best to use in assessing a particular character
state?  Hints are provided via abbreviations in the outline below.  b)  What are the features
associated with each character that will permit you to classify the state of that character? 
The NUMBERS in the following outline refer to feature numbers in the softwood datasheet. 
NA implies that you will not encounter this feature in your study of our selection of North
American woods.

GENERAL FEATURES

     Spring to summer wood transition in growth rings

         1.  Growth rings indistinct (NA). 
         3.  Latewood conspicuous eg. hard pines (2) X [29]

     Other general features are best determined by inspection of solid wood samples and  
     application of common sense.

         2.  Heartwood colored  Juniperus Wood Block [22]
         4.  Distinct odor  Juniperus Wood Block [22]
         5.  Distinct taste  Taxodium Wood Block [24] 
         6.  Greasy  Taxodium Wood Block [24]
         7.  Dimpled grain (NA)

LONGITUDINAL TRACHEIDS

         8.  Pits alternate (NA)
         9.  Pits > 1 seriate, opposite Pseudotsuga (14) R [27]
        10.  Tori scalloped (NA) although we will show you an example of strap like extensions 
              of tori in feature 51 Tsuga (12) R.
        11.  Spirals in earlywood Pseudotsuga (14) RT [27]
        12.  Callitroid thickenings (NA)
LONGITUDINAL PARENCHYMA

        13.  Parenchyma present Chamaecyparis (8) XRT Juniperus [22]
        14.  Parenchyma abundant Chamaecyparis (8) XRT Juniperus [22]
        15.  Parenchyma end-walls nodular Taxodium (10) T [24]

RAY TRACHEIDS 

        16.  Ray tracheids present (Larix, smooth not dentate)  (4) R [26]
   
  Dentate Ray Tracheids      
   
        17.  Minute Picea (7) R [25]
        18.  Average Pinus resinosa (11) R
        19.  Reticulate Pinus echinata (2) R [29]

RAY PARENCHYMA

    Horizontal Walls

        20.  Thin Taxodium (10) R [24]
        21.  Unpitted Taxodium (10) R [24]
        22.  Well pitted Picea (7) R [25]
   
    Other features

        23.  Indentures Taxodium (10) R [24]
        24.  Wall corners thickened Sequoia (9) T [23]
        25.  End walls nodular  Pseudotsuga (14) R [27]
        26.  > 30 cells high Sequoia,Taxodium (9,10) T [23,24]
        27.  Crystals present Abies (15) R

CROSS-FIELD PITS

        28.  1-3 Pinoid Soft pines (1) R [28]
        32.  1-6 Pinoid Hard pines (16) R [29]
        29.  Piceoid Picea (7) R [25]
        30.  Cupressoid  Chaemaecyparis (8) R [22]
        31.  Taxodioid Taxodium (10) R [24]

RESIN DUCTS

        33.  Normal vertical Pinus (1) XRT [28]
        34.  Traumatic (NA)
        35.  Horizontal  Pinus, Pseudotsuga (1,14) XRT [28,27]
        36.  Thick epithelial cell walls Pseudotsuga (14) XRT [27]

RESIN DUCTS
       
        Number of epithelial cells / horizontal canal T

        37.  5-6 Pseudotsuga (14) T [27]
        38.  7-12 Larix (4) T [26] 

GEOGRAPHIC REGIONS

        39-44,46-49 (NA)
        45.  North America         
            Time, resources, and scope of objectives limit this class to consideration of woods 
           endemic to the continent of North America.  That's not to say that there are not     
            plenty of woods worthy of your attention outside the scope of this class, we simply 
           do not have the time or money to investigate them.
        
PIT DETAIL

        50.  Notched pit borders Sequoia (9) R [23]
        51.  Tori extensions Tsuga (12) R

II.  Keying woods

1.  Use the Gymnosperm Wood Component of the MUDES to identify specimens [22] through
[29] in the wood identification collection.

ULTIMATE OBJECTIVE:  YOU WILL BE ABLE TO IDENTIFY 8 GENERA OF SOFT
(GYMNOSPERM) WOOD BY EITHER SIGHT OR MICROSCOPIC IDENTIFICATION BY
THE END OF THIS LABORATORY EXERCISE.