evolution

STREPTOPHYTE EVOLUTION origin of embryophytes (Charophyceae)

•vascular tissue •branched sporophyte •isomorphic phases •stoma

Anthocerotophyta

?

Polysporangiophyta

? ?

jackets multicellular sporophyte

flavonoids loss of pyrenoid

Bryophyta Marchiantiophyta

calyptrae stalked gametangia

loss of columella and stomata seta reduction

Classification and Differentiation of Anthocerotophyta • thalloid without internal differentiation • smooth rhizoids, cells with pyrenoid (only in algae) • sex organs embedded • sporophyte without seta, with stomates and columella, grows indeterminately, split longitudinally in two valves • multicellular elaters

Anthoceros

Classification of Bryophyta • Class Sphagnopsida

• Class Andreaeopsida • Class Polytrichopsida • Class Bryopsida

Sphagnum

Andreaea

Dawsonia

Hypnodendron

Differentiation of mosses • gametophyte: stem & leaves • sporophyte: single sporangium (capsule) on persistent stalk (seta) and elaborate structure for spore release (peristome) • calyptra: part of the gametophore covering the sporangium

Differentiation of mosses, the gametophyte • • • •

filamentous protonema multicellular rhizoids apical cell unistratose leaves, helically arranged • leaf cells often elongated • vascular tissue in stem and leaves

Differentiation of mosses, the sporophyte • more or less persistent seta • stomates in theca (capsule wall) • operculum and peristome usually present • no elaters among the spores • calyptra often elevated by growing sporophyte

Classification of Marchantiophyta • Class Marchantiopsida

• Class Jungermanniopsida – Subclass Metzgeriidae – Subclass Jungermanniidae

Conocephalum

Asterella

Pallaviciniaceae

Jungermannia

Differentiation of liverworts • sporophytes matures completely within the confines of gametophore, lacks stomates and columella • thalloid structure in both the marchantioid and some of the jungermannioid taxa

Differentiation of liverworts, the gametophyte • no extensive protonema, unicellular rhizoids • gametophores either thalloid or leafy, with leaves in two or three rows • leaves often complicate lobed • leaf cells usually isodiametric, often with trigones and oil bodies

Differentiation of liverworts, the sporophyte • no peristome, operculum, or stomates • no columella, but elaters among the spores • seta elongates after maturation of sporangium, and is ephemeral • calyptra stays at the base of sporophyte