Phylum Pterophyta Vascular Plants Without Seeds Ferns

Ferns: nonflowering vascular plants Spore-bearing leaves Horizontal undergound stems 1-2 feet tall Tropical ferns may grow as tall as 60 ft. with fronds ft. Some are epiphytes

Parts of a fern: Fronds – leaves Rhizome – a creeping or underground stem, which produce roots Sori – groups of spore-bearing sporangia (means “a heap”)

Fern Sori

Sporophyte Generation of Ferns A new fern’s life cycle typically begins in July with the appearance of sori on the undersurface or along the margins of a frond. Sori may be round, kidney-shaped, oblong, linear, curved or star-shaped.

Sporophyte Generation Sori appear on the underside of a frond. Sori first open and discharge millions of spores.

Gametophyte Generation Spore develops into a tiny green, heart- shaped structure called a prothallus. Seldom seen, only 1 cell layer in thickness.

Gametophyte Generation The underside of the prothallus develops archegonia and antheridia Antheridia near the point (sperm) Archegonia at notched end (ova)

Gametophyte Generation Sperm are released from the antheridia and swim to the ovum at the bottom of the archegonia.

Sporophyte Generation Zygote matures and sends the first leaf up and the first root down. The first leaf is often a fan-shaped blade. The second leaf is usually a fiddlehead, a coiled young leaf. Some fiddleheads are edible and used in salads.

Fern Alternation of Generation Facts Ferns usually require 3-7 years to reach reproductive maturity. Fern plants (sporophytes) live for several years and produce new fronds each year Protellia (gametophytes) only live 3-7 weeks, in which time they produce the archegonia and antheridia. Dominant generation: Sporophyte