1. Sphenophyta, Pterophyta
Lab 11
Sphenophyta, Pterophyta

2. Sphenophyta General features of the vascular plants
Common name: Horsetails
Synonyms: Arthrophyta
Sporophyte growth habit: Stems, leaves, roots
Gametophyte growth habit: Photosynthetic thalli

3. Sphenophyta Stele: Siphonostele
Undulipodia (“flagella”): Several whiplash
Sexual reproduction: Homosporous
Representative genera: Equisetum
Recognized by: Scale leaves in whorls; hollow stems; meiosporangia on sporangiophores

4. P Equisetum Sphenophyta
Left: Sterile shoots of an Equisetum with both sterile and fertile phases. Right: Close-up of a node of an Equisetum that only has one shoot form. Note the “crown” of non-photosynthetic scale leaves.
Sphenophyta

5. A Equisetum aerial stem
Note the pith canal, the vascular bundles (each with a xylem canal), and the cortical canals.
Sphenophyta

6. D Equisetum rhizome Sphenophyta
This riker mount shows a portion of a rhizome with roots and an aerial stem.
Sphenophyta

7. A Equisetum gametophyte
Left: Stereoscope view of a gametophyte. Right: Close-up of the gametangia.
Sphenophyta

8. D Equisetum gametophyte with embryonic sporophyte
On the lower right is the dark-stained embryonic sporophyte, with the root extending to the left and shoot to the right.
Sphenophyta

9. D Equisetum strobilus Sphenophyta
The yellow line shows where one would section this entire strobilus to see the view in the next slide. Note the hexagonal tops of the sporangiophores and the lighter meiosporangia hanging beneath them.
Sphenophyta

10. D Equisetum strobilus Sphenophyta
Above right: Low-magnification view of sectioned strobilus. Lower left: Close-up, showing sporangiophores with meiosporangia.
Sphenophyta

11. A Equisetum strobilus Sphenophyta
Left: Stereoscope view of strobilus. Right: Close-up of sporangiophores and meiosporangia.
Sphenophyta

12. A Equisetum meiospores
The two colors represent two different stain batches; there is no biological significance. The elaters are partially uncurled because of the steps taken to make the slide.
Sphenophyta

13. Pterophyta General features of the vascular plants Common name: Ferns
Synonyms: Pteridophyta, Filicophyta
Sporophyte growth habit: Stems, leaves, roots
Gametophyte growth habit: Photosynthetic thalli
Stele: Siphonostele or protostele

14. Pterophyta Undulipodia (“flagella”): Several whiplash
Sexual reproduction: Homosporous or heterosporous
Representative genera: Azolla, Cyrtomium, Marsilea, Osmunda, Polypodium, Salvinia
Recognized by: Meiosporangium with annulus (not in all); meiosporangia often in clusters (sori) on undersides of leaves

15. P Assorted ferns Pterophyta
Note the compound leaves, with petiole, rachis, and blades (some examples may have entire leaves). Most of these example ferns have rhizomes, which are either in the soil or on the surface.
Pterophyta

16. P Sori
This is the underside of a leaf of Polypodium, showing the sori. The next slides show the sori of Polypodium and other ferns.
Pterophyta

17. P Sori
Single sorus—note the yellow meiospores that have already been released.
Pterophyta

18. P Sori
Close-up of a sorus, showing the leptosporangia with their annuli.
Pterophyta

19. P Sori
This fern has an indusium— a flap of cells protecting the sorus.
Pterophyta

20. P Sori
This fern has a continuous sorus along the leaf margin.
Pterophyta

21. P Sori
Note the individual leptosporangia with annuli.
Pterophyta

22. A Osmunda rhizome Pterophyta
This is a low-magnification stereoscope view, showing the siphonostele (the pink ring to the right of center) surrounded by leaf traces and leaf petioles, as well as a few adventitious roots.
Pterophyta

23. A Osmunda rhizome Pterophyta
This is a high-magnification stereoscope view, showing the individual bundles of the siphonostele (red xylem surrounded by a thin layer of grayish phloem), the pith (with dark tannin cells), and leaf traces that correspond to leaf gaps in the siphonostele.
Pterophyta

24. A Marattia meiosporangia
This is a eusporangiate fern; the meiosporangia are fused into synangia.
Pterophyta

25. A Fern sporangia Pterophyta
These typical leptosporangia show the annulus. Each one of these nominally contains 32 meiospores, derived from eight meiocytes.
Pterophyta

26. A Cyrtomium sori Pterophyta
The shield at the bottom and its stalk form the indusium. Although the meiosporangia are sectioned, you can still see the annulus on some.
Pterophyta

27. P Fern gametophyte Pterophyta
The dark green plants on the lower left are gametophytes. The light green leaves belong to embryonic sporophytes.
Pterophyta

28. P Fern gametophyte Pterophyta
These gametophytes formed in a film of water on the lid of a soil plate, making their rhizoids especially easy to see. They have not yet formed gametangia.
Pterophyta

29. A Fern gametophyte fertilization
The gametophyte on the left only shows archegonia, and the ones on the right only antheridia.
Pterophyta

30. A Fern gametophyte with sporophyte
On the left is a very young sporophyte that only consists of a solid sphere of cells. On the right, the sporophyte has developed shoot and root, in addition to the foot. Be sure to distinguish gametophyte from sporophyte.
Pterophyta

31. D Fern gametophyte with sporophyte
These are demo slides of young sporophytes and their gametophytes.
Pterophyta

32. P Marsilea
Pterophyta

33. D Marsilea x.s. sporocarp
Note the megaspores and microspores inside this dormant sporocarp.
Pterophyta

34. D Germinating Marsilea sporocarps
Note the sporocarp, sorophore, and sori with mega- and microsporangia.
Pterophyta

35. D Germinating Marsilea sporocarps
Note the single megaspore, recently released from its sporangium, sitting on top of meiosporangia.
Pterophyta

36. D Marsilea male, female gametophytes
The large yellow objects are female gametophytes still inside their megaspore cell walls. They are surrounded by male gametophytes which will release sperm cells. The archegonia are located in the bumps emerging from the female gametophytes.
Pterophyta

37. P Azolla
The branching plants with tiny leaves are Azolla. The larger oval leaves belong to duckweed, a flowering plant.
Pterophyta

38. P Salvinia
The large leaves belong to Salvinia. To the lower right are some Azolla plants, and the green scum is Chlorophyta.
Pterophyta