LABORATORY 9:  FAMILY STUDIES - LILIOPSIDA (MONOCOTS I) 

1.    SUBCLASS VII - ALISMATIDAE - Sagittaria - Alismataceae -
Alismatales 

     Species of this genus are usually monoecious.  Examine both
staminate and pistillate flowers and construct a floral formula for
each.  Please work in pairs.  

     FLORAL FORMULA (staminate):                   DIAGRAMS:      
           

                                


     FLORAL FORMULA (pistillate): 
                                            
                                 


     Key to family.  Which floral characteristic allows you to
determine the proper class?___________________________________  

COUPLET SEQUENCE:
___________________________________________________________

    
_________________________________________________________________
_______ 

     In your opinion, with what dicot family would the Alismataceae
be most easily confused?
______________________________________________________________. 
     
     The Alismatidae represent a fundamental, relatively
unspecialized group of monocots, analogous to the Magnoliidae of
the Magnoliopsida.  What is "primitive" about the floral structure
of Sagittaria?___________________________    



2.    SUBCLASS VIII - COMMELINIDAE -  Tradescantia - Commelinaceae
- Commelinales 

     These spiderwort flowers are best observed in water (use a
small dish).  This flower shows advanced characteristics in
comparison to the apocarpous Sagittaria, but is primitive when
compared to elements of this subclass that have adapted to
anemophily (Cyperales).  Note the basic "monocot" floral plan,
i.e., 3 sepals, 3 petals, 3 connate carpels and 6 stamens.  The
pubescent filaments are characteristic of Tradescantia.  

      SKETCH:






3.  COMMELINIDAE - Avena (Oat) - Poaceae (Gramineae) - Cyperales  

     Flowers of this order are highly reduced in comparison to
those of the entomophilous Commelinales (see J & L p. 437 and wall
chart): the perianth has been reduced to lodicules; the flower is
simply 3 stamens and a compound pistil.  

Each flower is enclosed by two bracts: the larger bract (LEMMA)
usually encloses the smaller bract (PALEA) and the flower.  This
unit - two fertile bracts and the flower - is known as the FLORET. 
The floret is NOT the basic unit of a grass inflores-cence.  The
basic unit is the SPIKELET, a group of florets (sometimes just one)
subtended by two STERILE BRACTS (bracts not in direct association
with a flower) known as GLUMES (see fig. 14-108, J & L p. 437).
Identification of grass species requires an ability to recognize
this basic unit, the spikelet.

    Examine an oat spikelet.  Note the two basal glumes which
completely enclose the florets.  There should be three florets
above the glumes, with the terminal one not completely developed. 
Separate a palea from the larger lemma that encloses it.  Note the
flower.  Is there any structural difference between the palea and
lemma?  Look at the margins.  Diagram this Avena spikelet -
pointing out glumes, florets, and palea and lemma of one floret.  








Avena spikelet                                    Bromus spikelet 

     Obtain a Bromus spikelet and diagram its basic structure i.e.,
glumes and  paleas and lemmas of each floret.  Examine specimens of
other grass genera on display.  Be sure that you can identify the
basic unit of the inflorescence of each  -- the spikelet.  Label
your diagrams, and have your T.A. check these to make sure your
interpretation is correct.  


4.  COMMELINIDAE - Carex - Cyperaceae - Cyperales 

     Note the vegetative differences between Cyperaceae (sedges)
and Poaceae (grasses).  Examine a Carex floret.  Note PERIGYNIUM
surrounding the ovary--this is a feature only of Carex.  Examine
the Carex inflorescence.  It is made of "spikelet-like" units, but
the similarity between Cyperaceae "spikelets", and Poaceae
spikelets is superficial.  List two differences for grass and sedge
inflorescences. 

         
1._______________________________________________________________
_____  
         
2._______________________________________________________________
_______

     SKETCH OF OVARY AND PERIGYNIUM (Carex)          SKETCH OF
JUNCUS (see next page)






5.   COMMELINIDAE - Juncus (Rush) - Juncaceae - Juncales 

     Members of the Juncaceae (as well as the Cyperaceae) are
likely to be mistaken for Grasses (Poaceae).  Carefully examine
your Juncus specimen and construct a floral formula.  Note presence
of a PERIANTH in this family.  List two vegetative characters that
could be useful in distinguishing Juncus from a grass or sedge.  
SKETCH a Juncus flower on the previous page.

     1._______________________________   
2._________________________________ 

     Complete this lab exercise by filling in the comparison chart
below.  Concentrate on and list those features that consistently
characterize each family.  At the bottom of the page, make what
drawings or notes you need to tell the families apart.


Character            Poaceae             Cyperaceae         
Juncaceae            
 stems 
  round
  angled
  hollow
  solid
  pithy
                                                                  
             
 leaf/sheath 
  2-ranked
  3-ranked
  just sheath
  sheath open
  sheath closed
                                                                  
             
 flowers  
  perianth + or -
  bristles + or -
  lemma & palea + or -
                                                                  
             
 inflorescence
  glumes + or -
  spikelet + or -
  spikelet type
                                                                  
             
 fruit 
  capsule
  achene
  grain/caryopsis
                                                                  
             
 other?