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Bryophytes the second most diverse land plant group (BEHIND ONLY THE FLOWERING PLANTS) THERE ARE THREE MAJOR BRYOPHYTE PHYLA: Hepatophyta the “liverworts” approx. 6000–8000 species Anthocerophyta the “hornworts” approx. 150 species, Bryophyta the “mosses” approx. 10 000 species. “Bryophytes are characterized by an alternation of heteromorphic generations with the haploid generation (gametophyte) being the dominant phase of the life cycle,” (Etterson 2009). Simply refered to as “alternation of generations.” Plante: Bryophytes •Bryophytes are plants that lack vascular tissue. •They have a dichotomous branching pattern; a primitive type a branching. • They do not have vascular tissue in the midrib •(the “vein” located at the center of the haploid thallus). • 80% of species •Some “leaves” are 1-few cell layers thick Hepatophyta: The Liverworts Genus: Marchantia – Archegonia • The female sex organ • Located on the lower surface of the archegoniophore • Archegoniophore resembles a palm tree Genus: Marchantia – Antheridia • The male sex organ • Produced flagellated sperm • Appear on upper surface of antheridiophore • The antheridiophore resembles an umbrella Genus: Marchantia – Gemma cup with Gemmae • A specialized structure that allows liverworts to produce asexually. • Located on the upper surface of the thallus Kingdom: Plante Phylum: Hepatophyta Genus: Marchantia Genus: Riccia – Archegonia Haploid Genus: Riccia – Mature Sporophyte – Antheridium Haploid (1n) With Sperm Diploid (2n) Genus: Riccia •Thallus •Gametophyte plant body •Dichotomous branching •Lacks xylem and phloem ◦No true stem, true leaf or true root. •Utilizes hydroids (similar to xylem) and leptoids (similar to phloem) ◦In place of roots, rhizoids anchor bryophytes to a substrate Genus: Conocephalum Not native to Minnesota They grow only in humid locations Very small (~1-2 cm) Symbiosis with N-fixing bacteria Mature sporophyte is a long “horn-like” structure The gametophyte is the flat, green plant body Anthocerophyta: The Hornworts Genus: Anthoceros •Foot of Sporophyte •Sporophyte: horn-shaped ◦Grows from the base of the meristem ▪Instead of from the tip of the meristem, like other plants DISTINGUISHING FACTOR Genus: Anthoceros •Growing Sporophyte —It contains placental cells along with spores Genus: Anthoceros Fruiting Stem Rhizoids: Function like a root. Basil Meristem Horn-shaped sporophyte They are microphyllis (they do not have true leaves). Native to MN Conducting tissue known as Hadrom Water-conducting cells = Hydroids (no lignin, floppy if too tall) Food-conducting cells = Leptoids Multicellular rhizoids on gametophytes Bryophyta: The Mosses Genus: Mnium •Fruiting Stem •Antheridia w/ sperm •Haploid (1n) Genus: Polytricium •Live Specimen •Cross Section of a Stem Leptoids Hydroids Genus: Polytricium •The earliest haploid stage Gametophyte (protonema) •Spores develop into protonema, then into gametophytes Genus: Polytricium •Cross section of calyptra Leptoids •Longitudinal section of calyptra Hydroids •Calyptra is remnants of past archegonium Genus: Sphagnum •Protenoma •Leaves The Sphagnum has such high water holding capacity because it has expanded cells.
