1. Characteristics of the two groups of non-seed (seedless) vascular plants

2. 1) Lycophyta Commonly known as club mosses Sporophyta dominant
Leaves small arranged spirally, with vascular tissue
called microphylls
2 types of stele present:
Protostele (haplostele in Selaginella; actinostele & plectostele in Lycopodium)
Amphiphloic siphonostele (solenostele) in Selaginella

3. Lycophyta…
Spores produced in kidney-shaped sporangia in the axils of microphylls or in structures called strobili (strobilus)
Plants may be homosporous (Lycopodium) or heterosporous (Selaginella)
Gametophytes:
Spores germinate to produce gametophytes containing chloroplasts
Gametophytes considered autotrophic

4. Lycophyta- Lycopodium

5. Lycopodium spp

6. Lycophyta: Lycopodium strobilus-homosporous

7. Lycophyta: Selaginella

8. Lycophyta: Selaginella strobilus-heterosporous

9. 2) Pteridophyta- Fern Allies
Fern Allies--Whisk ferns and horse tails
1) Horse tails
Sporophyte consist of stem with small, wedge-shaped leaves & arranged in whorls (groups)
the stele is a eustele
spores are borne in sporangia in sporangiophores arranged in terminal cones
plants are homosporous, but spores develop into small female & male gametophytes
represented by one living genus, Equisetum

10. Horse tails: Equisetum sp

11. 2) Fern Allies-Whisk ferns
Most members are extinct (known from fossils only)
only two genera still living, Psilotum & Tmesipteris
Sporophyte consists of dichotomous branches with small leaf-like appendages
appendages are not supplied with vascular tissues
Rhizomes (subterranean stems) present
Stele a protostele (actinostele)
vascular tissue found in the stem only

12. Whisk fern- Psilotum sp

13. Fern Allies- Whisk ferns
Fertile aerial shoots bear tri-lobed structures called synangia
Synangia develop on enlarged apices of short lateral branches
results from fusion of 3 sporangia
Members are homosporous
Spores germinate to give achlorophyllous gametophytes
considered to be nutritionally saprophytic
Both archegonia & antheridia develop on the same gametophyte (monoecious)

14. Homospory vs heterospory
Plants which bear one type of spores are called homosporous plants
Usually produce a single type of gametophyte
With male and female reproductive organs (antheridia and archegonia)
Homospory only limited to early primitive plants
Heterospory:
Plants with two distinct types of spores are called heterosporous

15. Heterospory…
Sporophyte of heterosporous plants produce small spores (microspores) and large spores (megaspores)
A large number of microspores are produced in microsporangia protected by microsporophylls
Small microspores develop into male gametophytes or microgametophytes

16. Heterospory…
Sporophyte produces megaspores in megasporangia protected by megasporophylls
Megaspores develop into female gametophytes or megagametophytes
Only few, (4) megaspores are produced in a megasporangium

17. Heterospory
Gametophytes develop inside the spore walls; gametophytes reduced & well protected
Heterospory evolved in many plant groups
Heterospory appeared to give selective advantage to the plants
Considered to set a stage towards the evolution of the seed.

18. Life cycles Generalized cycle of homosporous non-seed vascular plants
(See pg 622, LIFE)
Generalized cycle of heterosporous non-seed vascular plants