Horsetails, clubmosses,and ferns: are primitive land plants, which, like higher plants, have stems, roots, and leaves, and vascular systems that transport water, minerals, and food. However, unlike higher plants, they do not produce seeds when reproducing. Their life-cycles involve two stages. In stage one, the sporophyte (green plant) produces spores in sporangia. In stage two, the spores germinate, developing into small, short-lived gametophyte plants that produce male and female gametes (sex cells); the gametes fuse to form a zygote from which a new sporophyte plant develops. Horsetails (phylum Sphenophyta) have erect, green stems with branches arranged in whorls; some stems are fertile and have a single spore-producing strobilus (group of sporangia) at the tip. Clubmosses (phylum Lycopodophyta) typically have small leaves arranged spirally around the stem, with spore-producing strobili at the tip of some stems. Ferns (phylum Filicinophyta) typically have large, pinnate fronds (leaves); sporangia, grouped together in sori, develop on the underside of fertile fronds.
Horsetails, clubmosses,and ferns: are primitive land plants, which, like higher plants, have stems, roots, and leaves, and vascular systems that transport water, minerals, and food. However, unlike higher plants, they do not produce seeds when reproducing. Their life-cycles involve two stages. In stage one, the sporophyte (green plant) produces spores in sporangia. In stage two, the spores germinate, developing into small, short-lived gametophyte plants that produce male and female gametes (sex cells); the gametes fuse to form a zygote from which a new sporophyte plant develops. Horsetails (phylum Sphenophyta) have erect, green stems with branches arranged in whorls; some stems are fertile and have a single spore-producing strobilus (group of sporangia) at the tip. Clubmosses (phylum Lycopodophyta) typically have small leaves arranged spirally around the stem, with spore-producing strobili at the tip of some stems. Ferns (phylum Filicinophyta) typically have large, pinnate fronds (leaves); sporangia, grouped together in sori, develop on the underside of fertile fronds.
