Phylum Pteridophyta and Lycopodiphyta

• MJ Korvan: 'Anyone can love a rose, but it takes a lot to love a leaf. It's ordinary to love the beautiful, but it's beautiful to love the ordinary.'
• Phylum Pteridophyta


  The first true land plants, comprises vascular plants that have a well-developed conducting system among cryptogams but do not generate seeds, fruits, or flowers
• Phylum Lycopodiophyta


  Comprises small, green, leafy organisms with spores but no flowers and seeds
• Lycophytes


  • Believed to be the oldest living lineage of vascular plants
  • Ancient Lycophytes were the most diverse and prevalent species of the time, ranging from to trees with trunks upto a third of a meter ( about 1 foot) or more in diameter
• Periods of seedless vascular plants (Lycophytes)


  • Silurian Period
  • Carboniferous Period
  • Devonia Period

  
• Microphylls


  • Leaves with a single, unbranched vein of vascular tissue
  • May have evolved from enations, scale-like appendages that later gained vascular tissue
• Rhizomes


  • Play a crucial role in anchoring the plant, absorbing water and nutrients from the soil, and producing new shoots
  • Essential for the survival and spread of lycophyte populations
• Strobili


  • Cone-like structures where sporangia are produced on leaves called sporophylls
• Homosporous


  Producing a single type of spore that gives rise to a bisexual gametophyte

  
• Heterosporous


  Producing two distinct types of spores
• Lycopodium (Ground Pines)

  • Small vascular plants found in diverse habitats worldwide, often in moist environments
  • Often grow on forest floors and resemble little Christmas tree
  • Usually upright
  • The stems are either simple or branched
  • Mostly less than 30 centimeters tall
  • The leaves may be whorled or spirally arranged
  • Adventitious roots, whose epidermal cells often produce root hairs, develop along rhizomes
  • Loose strobili is present at the tip of aerial stem
  • Reproduces through homospory, meaning it produces a single type of spore

  
• Selaginella (Spike Mosses)


  • Small, vascular plants found in various habitats worldwide, particularly in moist environments
  • Either a creeping, mat-forming growth (like a moss) or an upright branching growth (like a fern)
  • Small, scaly leaves on branching stems and has rhizophores
  • Approximately 700 species found worldwide, with a concentration in wetter areas, especially in the tropics
  • Tend to branch more freely than ground pines and have leaves with tiny appendages called ligules near the base
  • Exhibit heterospory, producing two different kinds of spores and gametophytes

  
• Life Cycle of Selaginella

  1. Sporophyte

  2. Gametophyte

  
• Isoetes (Quillworts)


  • Primitive vascular plants belonging to the group known as lycophytes
  • Typically inhabit wetland environments and are characterized by their small, spike-like leaves arranged in a spiral fashion around a stem
  • Quillworts, all belonging to the genus Isoetes, consist of approximately 60 species
  • Typically found in habitats where they are partially submerged in water for part of the year
  • Microphylls are slightly spoon-shaped at the base, resembling green porcupine quills but are not stiff and rigid
  • Microphylls are arranged in a tight spiral on a stubby stem, resembling the corm of gladiolus or crocus, with ligules occurring toward the leaf bases
  • Corms of quillworts have a vascular cambium and can live for many years, often being consumed by wading birds and muskrats
  • Generally less than 10 centimeters (4 inches) tall, although the leaves of some species can reach lengths of 0.6 meters (2 feet)
  • Reproduction is similar to that of spike mosses, but no strobili are formed. Both types of sporangia are produced at the bases of the leaves
• Life Cycle of Isoetes


  1. Sporophyte

  2. Gametophyte

  
• Comparison of Lycopodium, Selaginella, and Isoetes


  • Common Name
  • Habitat
  • Leaves
  • Stem
  • Number of Species
  • Reproduction

  
• Pteridophytes

  • The largest group of living seedless vascular plants—and probably the most familiar—are the ferns with about 12,000 species, over two‐thirds of which are tropical
  • Display differentiation-true root, stem, and leaves
  • First land vascular plants, so they are mostly terrestrial in nature, mostly growing in cool, moist and shady places. Some pteridophytes grow in xerophytic, semi-aquatic or aquatic conditions also
  • The main independent plant body is sporophyte with vascular system
  • All living pteridophytes are herbaceous except a few woody tree ferns
  • Most ferns are homosporous (all spores are same in shape and size); only two groups of water ferns (Marsileaceae and Salviniaceae) are heterosporous (spores are of two different shapesand sizes, smaller one called microspore and larger one megaspore)
  • Main mode of reproduction relies on spores as they do not produce flowers, seeds, fruit, or wood
  • Exhibit alternation of generations

  
• Roots


  • Simple, uncomplicated and arise adventitiously along the rhizomes near the base of the fronds
• Stems


  • Rhizomes that grow at, or just under, the ground surface. They have only primary tissues
• Leaves/fronds


  • Megaphylls with most being compound with a rachis and numerous pinnae (or compound with pinnules). Almost all have circinate vernation—they are coiled (circinate) tightly in "shepherd's crook" or crozier fashion over the growing tips
• Genera under Phylum Pteridophyta

  • Psilotophyta (Whisk Ferns)
  • Lycophyta (Club Mosses and Quillworts)
  • Equisetophyta (Horsetails and Scouring Rushes)
  • Polypodiophyta (Ferns)

  
• Life Cycle of a Fern

  1. Spores produced in sori on underside of leaf

  2. Spores germinate and grow into gametophytes

  3. Fertilization occurs, resulting in a diploid zygote

  4. Zygote develops into an embryo, which grows into a young sporophyte

  
• Pteris L. (Brake Ferns)

  • Tropical and subtropical ferns commonly grown as houseplants
  • Feature distinctive fronds with a central stalk, from which lance-shaped or oblong leaflets extend, giving them a feathery appearance
  • Propagate from short-creeping rhizomes, forming clusters of fronds
  • Exhibit dimorphic fronds, varying in shape and size, often arranged along a central stem

  
• Dryopteris (Wood Ferns)

  • Stand out among other ferns because of their intricate frond structure, often displaying pinnate or bipinnate forms with finely divided leaflets
  • Have a rhizomatous stem partially erect and partially horizontal where the apex projects above the surface of the soil
  • Known for their ability to tolerate a wide range of environmental conditions

  
• Polypodium (Rockap Ferns)

  • May display simple or pinnate fronds
  • Sporangia, the structures that produce spores, are often located on the undersides of the leaflets
  • Typically encountered in forests, along riverbanks, and even in urban areas

  
• Summary of Pteris L., Dryopteris, and Polypodium


  • Common Name
  • Habitat
  • Spore Production
  • Rhizome Morphology
  • Frond Structure