Today's non-seed producing vascular plants evolved from the forests of giants ferns present 300 million years ago. Today, the non-seed producing vascular plants are limited to ferns and fern-like plants. These descendants of the early fern forests are very similar to their ancestors. Spores from the adult plant reach the soil and develop into gametophytes, which then produce the adult sporophytes that mature and start the process all over again.
Like the club mosses, whisk ferns were among the first vascular plants to evolve. They are best described as a cluster of branched green stems that grow from a cluster of gametophytes. Unlike other non-seed producing plants, the whisk fern's gametophyte is non-photosynthetic and relies on bacteria in the soil to produce its food. The adults, however, are photosynthetic, producing their own food.
Club mosses are perhaps the simplest vascular plants. The reproductive parts grow at the top of stems in cone- or club-shaped structures, thus the name, club moss. The long, narrow leaf structures are a deep shiny green and are born on separate stems from the spore carrying cones. Club mosses were one of the first vascular plants to evolve, probably following only whisk ferns in development. The gametophyte is photosynthetic, producing its own food for growth.
Spikemoss and Quillwort
Appearing almost like the branches of a fir tree, the leaves of quillwort and spikemoss are needle-like structures that grow out from a stem. Also similar to the fir tree is the cone-like sporangia that produces the spores. The plant develops both megaspores, which develop into female plants, and microspores, which develop into male plants. The spores begin their development into gametophytes within the cone-like sporangia before being ejected to develop into individual plants.
These are long-stemmed plants in which most photosynthetic functions take place in the stems. The stems are segmented, dark green and bear the cones (sporangia) at the top. The plant does have leaves, although they are small, inconspicuous and grow from the stem segments. Horsetails prefer damp or wet environments.
Ferns have changed little in the last 350 million years, although species exist now that didn't exist then. Most ferns take a similar and familiar shape--a series of leaves arranged in a fan shape on a long stem. Ferns usually grow their spores on the undersides of their leaves, and turning one over will reveal the spore producing sporangia. Popular in the home and outdoors, ferns prefer warm, moist environments and do well in summer shade gardens or as houseplants.