FERNS AND FERN ALLIES

INCLUDE:
   1.     FERNS
   2.     PSILOPSIDS
  
3.     LYCOPSIDS
   4.     SPHENOPSIDS

FEATURES:

   1.     SEEDLESS, VASCULAR PLANTS
   2.     HAVE ALTERNATION OF GENERATIONS
   3.     SPOROPHYTE GENERATION DOMINANT

PSIL
OPSIDS

     CLASS:     PSILOPSIDA
     DIVISION: PSILOTOPHYTA

FEATURES:

     1.  BRANCHED, UNDERGROUND
RHIZOMES (STEMS)
         a.     ATTACHED TO THE SUBSTRATE BY UNICELLULAR                  RHIZOIDS
     2.     NO ROOTS
     3.     NO LEAVES (PSILO = BARE)

PSILOTUM 

     1.     SMALL (UP TO 61 CM)
     2.     ERECT, BRANCHED AXIS ARISING FROM A RHIZOME
          a.     HAS XYLEM AND PHLOEM
          b.     VASCULAR TISSUE SURROUNDED BY A CORTEX
                 1.     OUTER CORTEX IS PHOTOSYNTHETIC
                 2.     STOMATES PRESENT
     3.     SPORANGIA BORN LATERALLY ON THE STEM
          a.     MEIOSIS OCCURS IN THE SPORANGIUM
                 1.     SPORES GIVE RISE TO BISEXUAL                 
                                                           GAMETOPHYTES
     4.     GAMETOPHYTES ARE SUBTERRANEAN
          a.     NONPHOTOSYNTHETIC
          b.     ASSOCIATE WITH AN ENDOPHYTIC FUNGUS
          c.     SPERM PRODUCED ARE MULTIFLAGELLATE

LYCOPSIDS

      CLASS:        LYCOPSIDA
      DIVISION:     LYCOPODOPHYTA

FEAT
URES:
     1.     LEAVES VASCULARIZED BY A SINGLE, UNBRANCHED
            MIDVEIN
     2.     SPORANGIA ARE BORNE IN OR ON THE LEAF AXILS OR ON
            SPOROPHYLL

LYCOPODIUM AND SELAGINELLA

SIMILARITIES:

    
1.     AERIAL PORTION HIGHLY
BRANCHED
     2.     MANY SMALL, GREEN LEAVES PRESENT
     3.     ROOTS ARISE ALONG A HORIZONTAL STEM
     4.     SPORANGIA AGGREGATED INTO STROBOLI

DIFFERENCES:

    
1.     LYCOPODIUM HOMOSPOROUS
                 a.     GAMETOPHYTES ARE BISEXUAL
     2.     SELAGINELLA HETEROSPOROUS
            a.     MEGASPORANGIA PRODUCE MEGASPORES THAT GIVE
                   RISE TO THE FEMALE
GAMETOPHYTE
            b.     MICROSPORANGIA PRODUCE MICROSPORES THAT
                  GIVE
RISE TO THE MALE GAMETOPHYTE
     3.     GAMETOPHYTES OF HETEROSPOROUS PLANTS GREATLY
           REDUCED

ISOETES     (QUILLWORT)

     1.     HETEROSPOROUS
     2.     HAS STRAP SHAPED LEAVES
     3.     HAS A SHORT SUBTERRANEAN STEM
     4.     HAS ROOTS

SPHENOPSIDS

    
CLASS:        SPHENOPSIDA
     DIVISION:     SPHENOPHYTA

FEATURES:

     1.     LEAVES BORNE IN WHORLS
     2.     HAVE SPORANGIOPHORES (SPORANGIAL-BEARING
            STRUCTURES)


EQUISETUM

     1.     BRANCHED (HORSETAIIL)
     2.     UNBRANCHED (SCOURING RUSH)
     3.     SILICA IN EPIDERMAL CELLS
   4.     PHYSICAL FEATURES:
            a.     AERIAL PORTION ARISES FROM UNDERGROUND
                   RHIZOMES

           
b.     LEAVES UNITED LATERALLY,
FORMING A SHEATH
                   AROUND THE STEM
            c.     STEMS PHOTOSYNTHETIC
            d.     SPORANGIOPHORES AGGREGATED INTO STROBOLI
                         AT THE BRANCH TIPS
            e.     HOMOSPOROUS
                   1.     GAMETOPHYTES BISEXUAL
                   2.     GAMETOPHYTES CAN BE UNISEXUAL BASED
                         ON NUTRITION AND CROWDING
                     f.     ELATORS PRESENT
           g.     LARGE, MULTIFLAGELLATE SPERM