Families of Vascular Plants - Botany 307F

Diversity of Green Plants


|Introduction |Bryophyta |Pteridophyta |Pinophyta |Magnoliophyta|

"It was to Hofmeister, working as a young man, an amateur and enthusiast, in the early morning hours of summer months, before business, at Leipzig in the years before 1851, that the vision first appeared of a common type of Life-Cycle, running through Mosses and Ferns to Gymnosperms and Flowering Plants, linking the whole series in one scheme of reproduction and life-history." [A. H. Church (1919), quoted by E. J. H. Corner (1964)]

Portrait of Wilhelm Hofmeister from cover of American Journal of Botany 83(12), illustrating the Invited Special Paper on pp. 1647-1660 by D. R. Kaplan and T. J. Cooke, "The genius of Wilhelm Hofmeister: the origin of causal-analytical research in plant development." Originally published in K. von Goebel (1905), "The Plant World."

Wilhelm Hofmeister - 20.05 K

Green Plants; "Embryophyta"

...share a common life cycle involving alternation of sporophyte and gametophyte generations, with the embryo sporophyte retained within gametophyte at least initially. Features of this life cycle can be traced back to some of the earliest land plant fossils, such as the incredibly well-preserved materials from the Rhynie chert.
Map of green plant groups
Embryophyta also share photosynthetic pigments and storage polysaccharides with the green algae. However, they differ from the algae in their more complex structure and development. A common feature of all four plant groups described below that distinguishes them from the green algae is the formation of an embryo, or immature sporophyte, that is retained within gametophyte at least initially. Embryophyta phylogenies
Embryophyta phylogenies

Bryophyta

Gametophyte dominant, with microscopic structures for sexual reproduction; water-conducting tissue generally absent (the term "cryptogam" was applied to bryophytes, fungi, and algae to denote the microscopic nature of sexual reproduction in this paraphyletic assemblage of organisms lacking water-conducting tissue).

Vascular Plants; "Tracheophyta"

Waterproof cuticle, stomates, water-conducting tissue present; sporophyte dominant.

"Pteridophyta" or "Vascular Cryptogams"

Free-living gametophyte, with microscopic structures for sexual reproduction; motile sperm.

Seed Plants; "Spermatophyta" or "Phanerogams"

Gametophyte retained within tissue of parent sporophyte (=ovule; with development of embryo sporophyte, =seed); macroscopic sporophyte structures associated with sexual reproduction.

Ovules naked; Pinophyta or "Gymnosperms"

  • Cycadales; sperm motile
  • Gnetales; microgametophyte (pollen grain) germinates to form pollen tube, two nuclei (out of four) function as "sperm"
  • Ginkgoales; sperm motile
  • "Conifers"; microgametophyte (pollen grain) germinates to form pollen tube, two (out of six or more) nuclei function as "sperm"

Ovules enclosed; "Angiosperms;" flowering plants

microgametophyte (pollen grain) germinates to form pollen tube, two nuclei (out of three) function as "sperm" in double fertilization.

| What are plant families? | How do we distinguish them? | How and why do we study them? | Selected vascular plant families of Ontario | Reading List | Course outline |

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Please send your comments to tim.dickinson@utoronto.ca; last updated 14-Sep-2008