Sphenophyta, Pterophyta Lab 11 Sphenophyta, Pterophyta

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

P Sori Note the individual leptosporangia with annuli. Pterophyta

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

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

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

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

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

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

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

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

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

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

P Marsilea Pterophyta

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

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

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

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

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

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