1. Flowers - II

2. Carpel is composed of the stigma, style, and ovary and within the ovary are one to many ovules Ovules

3. Ovule begins developing as a bulge in ovary wall and soon a Megaspore Mother Cell (Megasporocyte) differentiates

4. The usual pattern of development Female Gametophyte

5. Whole Ovule View

6. Ovule is an integumented megasporangium. The wall of the megasporangium in known as the nucellus (nu)

7. Megaspore mother cell (MMC) prior to meiosis and after Division I Nucellus

8. MMC undergoes meiosis to produce 4 megaspores – in the majority of angiosperms, 3 degenerate

9. Surviving megaspore undergoes 3 mitotic divisions producing 8 haploid nuclei (cells)

10. Mature Ovule (Female Gametophyte)

11. 81% of angiosperms *** Occurs in Lilium

12. Other patterns

13. Pollen production occurs in the anthers Microsporangia

14. Cross section of unopened flower with 5 stamens

15. Young anther

16. Microspore mother cells differentiate in the microsporangia and undergo meiosis Tapetum

18. Microspores develops into male gametophytes

19. Tetrads

20. Pollen grains are the male gametophytes Microspore nucleus divides producing two nuclei (cells) Microspore wall becomes the pollen wall Pollen released at two cell stage in the majority of angiosperms

21. Gametophyte development

22. Pollen TEM

23. Pollen wall is an elaborate multilayered wall with sporopollenin as the “unique” component

24. Pollen is described by aperature type Pores Culpi (furrows)

25. Exine surface

26. More exine patterns

27. Orientation of the grain

28. Alnus (alder) pollen Juniperus (cedar) pollen Morus (mulberry) pollenQuercus (oak) pollen

29. Light and SEM views of ragweed and grass pollen