Pteradophyta : Fern Division

Note: Move cursor over image for note on what to look for. Click on image to enlarge.

• A: Plants with sporangia (spore producing bodies) in strobili (spore cone); or grape like cluster at end of a stalk; or in leaf axils:
• B: Plants with one pinnate leaf; Sporangia in grape like cluster at end of a stalk: Ophioglossaceae (Adders-tounge Family) 1 sps in our area: B.lunaria (Moonwort)
• B: Plants with sporangia in strobili; Leaves needle like, scale like, or appearing absent:
  • C: Stems with joints, Leaves appearing absent (leaves actually reduced to shethes around stem at joints): Equisetaceae (Horsetail Family)
  • C: Stems without joints; Leaves present needle or scale like:
  • D: Plants larger than most mosses; Strobili very distinct cone like structure: Lycopodiaceae (Club-moss family)
  • D: Plants not larger than most mosses; Strobili leafy or fleshy not so cone like: Selaginellaceae (Spikemoss Family)
• A: Plants with sporangia (spore producing bodies) on under side or edge of leaves:
• E: Fertile and sterile fronds (leafy branches) different; Sporangia on edges of curled up leaves of fertile fronds: Pteridaceae (Rock Break Fern Family) 1 sps. in our area: C.stelleria (Slender Cliff-break)
• E: Fertile and sterile fronds similar; Sporangia in sori (sporangia clusters) on underside of leaves:
• F: Fronds evergreen; Sori without inducia (covering): Polypodaceae (Polypody Fern Family) 1sps. in our area: P.sibiricum (Rock Polypody)
• F: Fronds decidious (withering in autumn); Sori with inducia (covering):
• G: Sori elongate; Leaf viens not reaching leaf edges: Asplenaceae (Spleenwort Fern Family) 1sps. in our area: A.trichomanes (Green Spleenwort)
• G: Sori round; Leaf viens reaching leaf edges: Aspidiaceae (Fern Family)

Natural History:

The Pteridophytes (spore bearing vascular plants) have been around for 408 milloin years. The classes in this division represent some of the oldest lineages of land plants. The Lycopodopsida (clubmoss class) was the first branch of the evolutionary tree. Later the Equsitopsida (horsetail class) would split from the Ferns. From about 360MYA many of the Pteridophytes had developed to become very large trees. Clubmoss, horsetail and fern trees dominated earths land vegitation for more than 100 million years. It is the remains of these giant Pteridophytes that would over eons become the fossil fuels we use today. The time period of the giant Pteridophyta forests is known as the carboniferious period. Eventualy some species developed the ability to reproduce by seeds. One of these groups the Pteridosperms (seed ferns) would be the ancestors of the Gymnosperms (naked seed plants) and all modern seed plants.

Life Cycle:

The life cycles of the different classes and families of the Pteridophyta are quite unique. They do though share some common charactarists. In the Pteridophyte division both the sporophyte and gametophyte generations live as free living plants. The sporophyte is much larger and longer lived than the gametophyte. It is the dominant generation and what we recongnize as ferns, clubmosses, et cetera. Though most Pteridophytes are homosporus producing spores of the same size and of no particular gender, some species are heterosporus which means they produce spores of different sizes and genders. Heteropory is found in different classes and families showing that it is a polyphyletic (not one ancesteral sps) charactaristic that was eveolved independently a number of times. Diagrams and discusions of the different life cycles will be on the family pages for this division.