1. Seedless Vascular Plants

2. Lycopodiophyta: Lycophytes Pteridophyta: Ferns
Lycophytes = club mosses also include the spike mosses and Quillworts
Lycopodiophyta: Lycophytes
Pteridophyta: Ferns
4 orders of true ferns +
Psilotales: Whisk ferns Equisetales: Horsetails

3. Characteristics of the Seedless Vascular Plants
Vascular tissues (protostele, siphenostele, few have eustele)
Well developed cuticle
Lignin & cellulose in secondary wall
Protected Sporangia
In most, sporangia are aggregated into strobili
Have dominant sporophytes
Require water for fertilization

4. Leaves in the Seedless V. P.
Microphylls mostly associated with protostelic stems, no leaf gaps, common lycophytes
Megaphylls: associated with stems that have siphonostele or eustele, have leaf gaps
evolved as fusion of branch systems
Enations: scale-like outgrowth devoid of vascular tissues
Microphylls: evolved from enations, with a single vein
Megaphylls: evolved as modified branches, have branched veins

5. Phylum Lycopodiophyta: Lycophytes
Mostly tropical
Consist of 3 living orders each with a single family
All living genera are herbs with microphylls
Consist of 3 living orders each with a single family (Club mosses, spike mosses, & quillworts)

6. Club Mosses: F. Lycopodiaceae
Example: The genus Lycopodium *
All living genera, except two, are classified in this family
Seven genera are represented in U.S. & Canada but most species are tropical & epiphytes
Roots & stems are protostelic
Homosporous, sporangia are in axils of fertile leaves (sporophylls)
In Lycopodium, sporophylls are grouped into strobili *
Sporophyte consists of branching rhizomes.

7. Lycopodiella inundata
Lycopodium obscurum
Lycopodiella inundata
Locopods
Modern members of the Lycopodophyta are relatively small plants, many with creeping rhizomes bearing upright branches.
Lycopodium obscurum is a common club moss of northern forests
Lycopodiella inundata grows in some bogs in our area. It can survive extended immersion in shallow water
Spores are produced in sporangia, tiny sac-like organs born at the base of leaves near the tip of the stems
The sporangium bearing leaves are often packed into a dense, cone-like structure (Strobilus)

8. Lycopodium digitatum

9. An Epiphytic Club Moss

10. Spike Mosses: F. Selaginellaceae
One genus Sellaginella (700 species)*
Tropical, many found in moist habitats, few are desert plants
Sporophylls arranged in strobili (Heterosporous)*
Has micro- & megasporophylls
Microsporangia are carried on upper portion of the strobilus
Has microsporophylls (fertile leaves carry microsporangia)
Has megasporophylls (carry megasporangia)

11. Selaginella denticulata

12. Sporangia (Selaginella underwoodii)

13. Selaginella arbuscula

14. Selaginella involvens
Selaginella apoda
Selaginella
Selaginella involvens
Two species of Selaginella grow wild in New York State, S. apoda and S. rupestris
S. involvens is a native of Eastern Asia; this specimen is cultivated in the Brooklyn Botanic Garden.
Broad arrow that appears on click is link back to group slide

15. Selaginella spp

16. Resurrection Plant (Selaginella lepidophylla)
Desert plant: Found in TX, NM, and Mexico

17. Quillworts: F. Isoetaceae
One genus Isoetes*
They are aquatic, or found in seasonally flooded habitats
Plants look like grasses, with underground stem (corm)
All leaves are potential sporophylls
Heterosporous, lower leaves are megasporophylls, upper microsporophylls

19. Quillworts: Microsporangia & Microspores

20. Quillworts: Megasporangia & Megaspores

21. Quillworts: Habitat

24. Pteridophyta: Psilotales Whisk Ferns
Consist of one family & two genera
They are the simplest vascular plants
Represent an early lineage related to living ferns

25. Wisk Fern: Genus Psilotum*
Tropical and subtropical in distribution (S. States)
Protostelic
Lacks roots, has rhizomes & rhizoids
Leaves are represented by enations
Dominated sporophyte, homosporous
Gametophyte is heterotrophic, either symbiotic or parasitic on soil fungi
Xylem consists of thick tracheids,

26. Psilotum Sporophyte
Sporophyte

27. Psilotum nudum

28. Psilotum nudum
Sporangia

29. Wisk Fern: Genus Tmesipteris
Sporangia
Confined to South Pacific
Grows as an epiphyte on tree ferns & other plants
Has microphylls

30. Pteridophyta: Equisetales Horsetails
Represented by 1 genus, Equisetum (horsetails)*
It is the oldest survivor of plants
Widespread in moist habitats and edge of forests
Has jointed stem (nodes) & rough texture
Has microphylls
Homosporous, sporangia are clustered into strobili
Recognized by its jointed stem (nodes) & rough texture Stems arise from underground rhizomes (eustele)
Some species have fertile and sterile stems
Gametophyte is green and free living (size of a pinhead)

31. Strobilus
Branches
Leaves
Equisetum arvense

32. Equisetum is the only living genus in the Equisetophyta
The stems of horsetails are constructed somewhat like those of bamboo, with internodes of regular length separated by nodes each of which bears a whorl of tiny leaves
In those species that form branches, the branches also occur in whorls at the nodes
E. arvense produces short-lived, non-photosynthetic fertile shoots in the spring followed by these branched green shoots that live all summer
The underground rhizome lives for many years
Equisetum arvense

33. Equisetum hyemale E. hyemale rarely produces branches
As with other species of Equisetum, the sporangia are born in strobili at the tips of the stem
Broad arrow that appears on click is link back to group slide

34. Phylum Pteridophyta: True ferns:
The largest group of living seedless vascular plants (11,000 spp)
They are found in a variety of habitats
3/4 are tropical
1/3 of tropical ferns grows as epiphytes
1/4 inhabits temperate regions & desert
Ferns are second only to flowering plants (235,000 spp)

35. Polystichum acrostichoides
Sporangia are produced on the underside of the terminal portion of the leaf in P. acrostichoides

36. Dryopteris carthusiana (mature sporangia)
Mature fern sporangia are barely distinguishable to the unaided eye
Broad arrow that appears on click is link back to fern life cycle
Dryopteris carthusiana (mature sporangia)

37. Fern: Morphology
Most ferns of temperate region produce annual leaves from subterranean rhizomes
Leaves are megaphylls (fronds), constitute major part of the sporophyte
Ferns are the only seedless vascular plants with megaphylls
Most ferns are homosporous, water ferns are heterosporous

38. Fern Morphology Frond: compound leaf of ferns Pinnae (leaflet)
Rachis (extension of petiole
Petiole: leaf stalk

39. Fern Spores
Sorus

40. Fern Gametophyte
Archegonia
Antheridia
Rhizoid

41. Text Pg. 567
Fern Life Cycle
Click on the broad arrow at upper right to go to photos of fern sporophytes and sporangia
The broad arrow that appears at lower right after a click on this slide is a link to the next section of the presentation
Although there are differences in the details, the fern life cycle shares many characteristics with the life cycles of other seedless vascular plants
The large photosynthetic and usually long-lived sporophyte is the plant we usually recognize (contrast with mosses and liverworts)
Spores are produced by meiosis in a sporangium
Spores are usually dispersed by the wind
Spores germinate to grow into a small, inconspicuous gametophyte which may be photosynthetic (in ferns) or may be subterranean and dependent on association with soil fungi for nutrition (in some species of other groups)
Gametes (eggs and sperm) are produced in Gametangia (archegonia and antheridia) produced on the gametophyte
Sperm are flagellated, motile, and require the presence of liquid water in which to swim to the archegonia, enter them, and fuse with the egg
The zygote divides to form an embryo which develops into a functional young sporophyte while still attached to the gametophyte

42. Diversity of Ferns

43. Pteridium aquilinum (Common Brake)

44. Athyrium filix-femina var. angustum (Lady Fern)

45. Dryopteris intermedia (Common Wood Fern)

46. Matteuccia struthiopteris (Ostrich Fern)

47. Onoclea sensibilis (Sensitive Fern)

48. Water Ferns Include two orders: Marsileales & Salviniales
Constitute the only living heterosporous ferns
Marsiliales – Marsilea
Salviniales – Salvinia & Azolla

49. Marsilea spp.
Resembles a four-leaf clover. Grow on mud or submerged with floating leaves

50. Marsilea spp Sporocarp (at base of plants)

51. Salvinia: Aquatic Habitat
Small plant, float on surface of water

52. Aquatic Fern: Salvinia
Has undivided leaves
Plants float freely

53. Salvinia: Leaf & Hairs
Hairs protect leaf from getting wet & allow them to remain above water

54. Aquatic fern: Azolla Weed of the Rice paddies Has bilobed leaves
Leaves have pouches that harbor the nitrogen-fixing bacteria (Anabaeana)
Azolla spp.

55. Cyanobacteria such as Nostoc & Anabaena possess a heterocyst where nitrogen fixation takes place
Azolla caroliniana

56. Azolla caroliniana at Rice Creek Pond (red)
Azolla caroliniana at Rice Creek Pond (red). The other plants are duckweeds.

57. Azolla caroliniana on Mud