BOT 360F - Families of Vascular Plants

Quiz 5 20-Oct-11

 

(1) Sketch a generalized gymnosperm ovule, clearly distinguishing between the embryo sporophyte and components form by the parent sporophyte and by the megagametophyte; label fully.

Ginkgo ovule

(2) What are the differences between eusporangiate and leptosporangiate sporangia? For extra credit, for each type of sporangium give an example of a genus in which that sporangial type occurs.

  • Development; eusporangiate sporangia develop from the inner daughter cell (i. in the diagram below left) following a periclinal division in the epidermis of a sporophyll primordium. Leptosporangiate sporangia develop from the outer daughter cell (o. in the diagram belowleft).
  • Mature anatomy; eusporangiate sporangia are thick-walled, the walls being more than one cell layer thick (e.g. Botrychium sp., below, center). The walls of leptosporangiate sporangia are only a single cell layer thick (fern sorus, below, right).
  • Lycopodium, Huperzia, Selaginella, Equisetum, and Psilotum are all examples of Pteridophyte genera with eusporangiate sporangia. Seed plants are similar.
  • Most of the "ferns" seen in the lab on 20 October 2011 were leptosporangiate ferns.

    Pteridophyte life cycle

Botrychium sporangium Fern sorus

Click HERE for Quiz 5 in 2010.


| 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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