1. STREPTOPHYTE EVOLUTION origin of embryophytes
4/26/2017
STREPTOPHYTE EVOLUTION origin of embryophytes
(Charophyceae)
Anthocerotophyta
Polysporangiophyta
Bryophyta
Marchiantiophyta
vascular tissue
branched sporophyte
isomorphic phases
stoma ? ?
jackets
multicellular sporophyte ?
Evolution:
Goffinet, B (Origin and phylogenetic relationships of bryophytes. In Shaw, A. J. and B. Goffinet (eds.). Bryophyte Biology. Cambridge University Press. Pp ), Fig Hypothesized character-state reconstructions for the ancestor to the embryophytes and to clades composed of extant land plants. Whether isomorphic phases and the ability of the sporophyte to branch were innovations that arose in the ancestor to the Polysporangiophyta only, or in a lineage preceding the divergences between the moss + liverwort clade and the Polysporangiophyta, remains open to debate. Similarly the origin(s) of the stoma and of the water-conducting cells remains unresolved.
flavonoids
loss of pyrenoid
calyptrae
stalked gametangia
loss of columella and stomata
seta reduction
evolution

2. Classification and Differentiation of Anthocerotophyta
4/26/2017
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
Classification and Differentiation of Anthocerotophyta (hornworts):
The most recent treatment is found in K.S. Renzaglia and K.C. Vaughn, 2000 (Anatomy, development, and classification of hornworts. In Shaw, A. J. and B. Goffinet (eds.). Bryophyte Biology. Cambridge University Press. Pp )
The hornworts are now considered as the oldest still extant lineage of land plants. Six of 11 genera have recognized wide recognition. Approximately 400 species have been described, but the number is probably greatly exaggerated (Schofield, W.B Introduction to Bryology. MacMillan Pub. Co., New York pp.)
They are distinguished from the mosses and liverworts by the following:
the gametophore is thalloid without internal differentiation, in contrast with that of the Marchantiales. Rhizoids are smooth. Each cell has a single chloroplast with a pyrenoid, which is otherwise found only in algae. Often cavities within the thallus are invaded by the blue-green alga Nostoc. It is the only land plant which forms gametophytic stomates.
the sex organs are embedded in the thallus, but are formed from superficial cells. Antheridia are discrete organs, but the archegonial wall is not differentiated from the surrounding thallus cells.
the first division of the zygote is longitudinal in contrast with the transverse division in liverworts and mosses. The sporophyte has no seta, grows indeterminately from an basal intercalary meristem, and resembles a grass blade. It matures at the apex and shed spores while new ones are formed by the meristem below. A calyptra sometimes protects the sporophyte and a basal part forms a protective involucre. The sporangium dehisces along one or two longitudinal slits. Its wall is multistratose and possesses stomates. There is a central columella. The are multicellular elaters among the spores.
evolution

3. Anthoceros Bryophyte groups: 4/26/2017
Anthoceros agrestris, hornwort gametophyte and sporophytes (Frahm Lebermoose und Trofmoose Deutschlands, 2000)
The hornworts are the smallest and most isolated group among the bryophytes, probably with not more than about one hundred species, in either 4 or 6 genera. They are widespread in tropical and temperate climates, and are found most frequently on mineral soils of banks, cliffs, and along streams.
Anthoceros
evolution

4. Classification of Bryophyta
4/26/2017
Classification of Bryophyta
Class Sphagnopsida
Class Andreaeopsida
Class Polytrichopsida
Class Bryopsida
Classification of Bryophyta (mosses):
The mosses are the largest group among the bryophytes with 12,800 species and 901 genera presently recognized (Crosby, M.R., R.E. Magill, B. Allen, and S. He. A checklist of the mosses. Missouri Botanical The diverse group is further classified into several clear evolutionary lineages, based on the structure of the sporangium.
Vitt et al (8. The ordinal classification of the mosses: questions and answers for the 1990s. In Bates, J.W., N.W. Ashton, and J.G. Duckett, Bryology for the Twenty-first Century, Maney & Son Ltd, London. Pp ) recognizes four classes, most parsimonious with molecular data and consistent with morphological data:
Sphagnopsida with only Sphagnum, excluding Protosphagnum whose position is uncertain, but now also including Ambuchanania.
Andreaeopsida containing Takakia, Andraeobryum, and Andreaea, defined by capsules with splits
Polytrichopsida for all the nematodontous mosses (peristome teeth composed of entire cells)
Bryopsida for all the arthrodontous mosses (peristome teeth composed of cell plates)
evolution

5. Sphagnum Classification of Bryophyta, Sphagnopsida: 4/26/2017
Sphagnum lindbergii, R.M. O’Clair 1987, Alaska
Recently a genus in addition of Sphagnum (with approximately 150 species ) has been recognized, Ambuchanania with one species). The fossil genus Protosphagnum is excluded.
Sphagnum
evolution

6. Andreaea Classification of Bryophyta, Andreaeopsida: 4/26/2017
from
Traditionally two genera composed this class, Andreaea with approximately 100 species, and Andreaeobryum with one. Takakia has also been added (previously considered a liverwort in the Calobryales) (Vitt et al. 1998) or is considered as its own order, Takakiopsida (Buck & Goffinet 2000). The latter also separate Andreaeobryum in the Andreaeobryopsida (cladistic influence).
Andreaea
evolution

7. Dawsonia Classification of Bryophyta, Polytrichopsida: 4/26/2017
Dawsonia superba, J.-P. Frahm, Moose Neuseelands
This class contains all the previous nematodontous orders (with at least some of the peristome teeth composed out of entire cells): Buxbaumiales (4 genera, 39 species), Tetraphidales (2 genera, 5 species), and Polytrichales (19 genera, ± 370 species).
evolution

8. Hypnodendron Classification of Bryophyta, Bryopsida: 4/26/2017
Hypnodendron comatum, J.-P. Frahm, Moose Neuseelands
largest class within the phylum Bryophyta, with arthrodontous peristome: well over 9,000 species, more than 95% of the mosses, approximately 90 families, 650 genera.
evolution

9. Differentiation of mosses
4/26/2017
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
evolution

10. Differentiation of mosses, the gametophyte
4/26/2017
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 gametophyte:
The moss gametophyte is distinguished from that of the hornworts and liverworts by the following characteristics:
the protonema is filamentous, branched, and extensive.
the rhizoids are multicellular. They are often dense and form a felted mat: the tomentum. The cells are brown-walled, with oblique septae, and either smooth or papillose (with little warts).
the stem apex of the gametophore grows by the production of cells formed from an apical cell.
most gametophores have isophyllous, unistratose leaves (except for the costa), which are helically arranged in a 5/2 phyllotaxis or rarely, in 3 ranks. They are rarely lobed. Moss leaves are unistratose (one-cell thick) except for a single or double costa (not always present) and sometimes a reinforced border (differentiated margin). There is no petiole and the leaves are commonly hygroscopic, folding up against the stem (imbricate) or contorted when dry.
the leaf cells are commonly elongate, and rarely possess trigones (triangular corner thickenings). In addition to the differentiated cells of the border and costa, those located on the outside of the leaf in a triangular area near the insertion with the stem are often enlarged or shaped differently (alar cells, alar region).
sometimes there is a differentiated vascular system in either the stems, setae, or thicker costae, but it is never lignified and probably evolved independently from the vascular system of the tracheophyte sporophyte (analogous).
evolution

11. Differentiation of mosses, the sporophyte
4/26/2017
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
Differentiation of mosses, the sporophyte:
The moss sporophyte is distinguished from the that of hornworts and liverworts by the following characteristics:
the young sporophyte develops from an apical meristem (forming the seta and sporangium) and a basal meristem (forming the foot that penetrates into the gametophore tissue; the calyptra is torn loose by the expanding sporophyte and elevated by the sporangium above the gametophore. The sporangium is elevated on a persistent stalk (seta) before the spores mature and is frequently photosynthetic during development.
the multistratose sporangium wall generally has stomata. Within the sporangium there is usually a central sterile column, the columella; there are no elaters (sterile cells) found among the spore tetrads; The sporangium opens by means of an apical lid (operculum) and the mouth is usually surrounded by teeth, comprising the peristome, which control the release of the spores.
evolution

12. Classification of Marchantiophyta
4/26/2017
Classification of Marchantiophyta
Class Marchantiopsida
Class Jungermanniopsida
Subclass Metzgeriidae
Subclass Jungermanniidae
Classification of Marchantiophyta (liverworts):
The most recent treatment is found in B. Crandall-Stotler and R.E.Stotler, 2000 (Morphology and classification of the Marchantiophyta. In Shaw, A. J. and B. Goffinet (eds.). Bryophyte Biology. Cambridge University Press. Pp )
“there are an estimated 6,000 to 8,000 species of liverworts, at which at least 85% are leafy jungermannioids”
evolution

13. Conocephalum Asterella
4/26/2017
Conocephalum
Classification of Marchantiophyta, Marchantiopsida:
Conocephalum conicum (L.) Lindb., Juneau area localities, Alaska (O’Clair 1987)
Asterella sp., J.-P. Frahm, Moose Neuseelands
Consisting of the old orders Sphaerocarpales (3 genera/32 species), Monocleales (1/2), and Marchantiales (270/450) (Schofield, W.B Introduction to Bryology. MacMillan Pub. Co., New York pp.)
Asterella
evolution

14. 4/26/2017
Classification of Marchantiophyta, Jungermanniopsida, subclass Metzgeriidae:
Symphyogyna oder Podomitrium, J.-P. Frahm, Moose Neuseelands
The Jungermanniopsida consisted of the old orders Calobryales (2 genera/14 species, but Takakia now considered and Bryophyta), Jungermanniales (280/7000), and Metzgeriales (28/550) (Schofield, W.B Introduction to Bryology. MacMillan Pub. Co., New York pp.)
Pallaviciniaceae
evolution

15. 4/26/2017
Classification of Marchantiophyta, Jungermanniopsida, subclass Jungermanniidae:
Jungermannia hodgonsiana, J.-P. Frahm, Moose Neuseelands
Jungermannia
evolution

16. Differentiation of liverworts
4/26/2017
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
evolution

17. Differentiation of liverworts, the gametophyte
4/26/2017
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 gametophyte:
no extensive branched protonema is formed and rhizoids are unbranched and unicellular.
the gametophore is either thalloid (the origin of the term “liverworts”, shaped as a liver) or more commonly leafy, but in those groups the leaves are arranged in three or two rows, which is rarely the case in mosses.
leaves have no costa and are often lobed or folded in complicated shapes, and the leaf cells are mostly isodiametric (round or stellate in shape), often with trigones and oil bodies.
evolution

18. Differentiation of liverworts, the sporophyte
4/26/2017
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
Differentiation of liverworts, the sporophyte:
the sporangium is thin-walled, doesn’t have stomates, and dehisces along four longitudinal lines, without an operculum or peristome. The columella is absent, and instead sterile cells are found among the spores, the elaters.
the sporangium is elevated only near maturity above the gametophore by an ephemeral stalk (seta), persisting for a very short time after the spores have been quickly dispersed. The calyptra remains at the base of the seta.
evolution