Seedless Vascular Plants

Characteristics Lycophyta Sphenophyta PterophytaCommon Organisms

Club Mosses Horsetails Ferns

Watertransportation

By vasculartissue

By vasculartissue

By vasculartissue

Structure Look like miniature pinetrees; scalelikeleaves

True leaves,stems, and roots

Creeping orundergroundrhizomes (stems);fronts (leaves);some have noroots or leaves

Comparing Spore-Bearing Vascular Plants

Seedless vascular plants

General Characteristics

• Seedless vascular plants include ferns, whisk ferns, club mosses, and horsetails.

• The plants do not produce seeds so, like bryophytes, they are dispersed (spread) by windblown spores.

General Characteristics• Most species are homosporous, meaning they

produce only one type of spore. • The gametophyte and sporophyte are

independent.• They can produce a separate male or female

gametophyte or bisexual gametophytes, the condition is known as homospory

General Characteristics• Some are heterosporous, can produce two

types of spores megaspore and microspore• Macrosporangia produces megaspore and

microsporangia produces microspore.• Megaspore produces female gametophytes

and microspore produces male gametophytes

Seedless vascular plants

• They are vascular plants and therefore have true roots, stems, and leaves.

• The sperm are flagellated and require water for reproduction. These plants are therefore limited to moist areas.

Seedless vascular plants• Many of the seedless vascular plants were

once tree-sized. • During the carboniferous period (near the end

of the Paleozoic), these plants were so abundant that in some areas, their remains accumulated faster than they decomposed. These accumulations produced our fossil fuels.

Seedless vascular plants

• The earliest known vascular plants had a pattern of branching that increased the number of sporangia.

• Leaves of later plants probably evolved from webbing between the branches.

Phylumm Psilophyta

• Consits of 142 species• Most species is

commonly known as Whisk ferns

• Group consisting of two extant genera, Psilotum and Tmesipteris, in one family, Psilotaceae.

Phylumm Psilophyta

• These plants are primitive in structure: Psilotum lacks both roots and leaves and is structurally similar to the fossil genus Rhynia.

Rhynia- one of earliest

vascular plants(ca. 400 million years

ago)

- lacked roots

Phylumm Psilophyta

• Recent molecular systematic studies suggest that the family is actually related to primitive ferns.

• Tmesipteris has a more complex morpholgy in that it has structures on the aerial shoot that are foliar.

Phylumm Psilophyta

• Both Psilotum and Tmesipteris have compound sporangia called synangia. In the case of Psilotum these are three-parted.

Phylumm Psilophyta

Phylumm Psilophyta• While Psilotum lacks true

leaves, it possesses leaf-like extentions of the stem called enations.

• Because these lack vasculature, they are not considered leaves. However, in Psilotum complanatum, a vascular trace occurs below the enations. The foliar structures of Tmesipteris are vascularized.

Phylumm Psilophyta

• The gametophytes of both genera are non-photosynthetic and live in association with a fungus.

• In the case of Psilotum, the gametophyte of certain strains produce vascular tissue.

Phylumm Psilophyta

• While both genera have aerial branches arising from stems embedded in its substrate, they both lack roots. The rhizomes are infected with mycorrhizae.

Phylum Lycophyta• Ancient Lycophytes• Appeared 390 million years ago

(mya)• Grew to 30 m tall• Extremely abundant due to the

moist warm environment• Most died out 280 may due to a

new drier cooler environment• include Lycopodium and

Selaginella

Lycopodium

Selaginella

Phylum Lycophyta

Modern Lycophytes• Much smaller than ancestors• Grow close to the ground• Found mainly in moist/damp forests• Can be found in deserts and mountains though• AKA the Club mosses and Spike mosses• because they look like the moss gametophytes—

but they are NOT MOSSES!• Sporophyte generation is dominant

Lycophyta Leaves andreproduction?

• Leaves protect the reproductive cells• Leaves occur in spirals, whorls, pairs• Leaves form clusters called STROBILUS at the end

of stems.

Lycophyte Reproduction/Life Cycle:

• Sporangium burst and release spores• Prothallus: gametophytes formed from

spores; relatively small; lives in or on the soil; form both archegonia and antheridia;

• In some lycophytes, 2 types of spores form Small spores: become male prothallus – Form antheridium

Lycophyte Reproduction/Life Cycle:

• Large spores: become female prothallus– Form archegonium

• Sperm from the antheridiumswim through a film of water on the prothallus to the egg in an archegonium and fertilize the egg.

• Then a sporophyte plant grows from the zygote.

Lycopodium• genus of clubmosses, also known

as ground pines, in the family Lycopodiaceae, a family of fern-allies (see Pteridophyta).

• They are flowerless, vascular, terrestrial or epiphytic plants, with widely-branched, erect, prostrate or creeping stems, with small, simple, needle-like or scale-like leaves that cover the stem and branches thickly.

Lycopodium

• The fertile leaves are arranged in cone-like strobili.

• Specialized leaves (sporophylls) bear reniform spore-cases (sporangia) in the axils, which contain spores of one kind only. These club-shaped capsules give the genus its name.

Lycopodium• Lycopods reproduce sexually by spores.

The plant has an underground sexual phase that produces gametes, and this alternates in the life cycle with the spore-producing plant.

• The prothallium developed from the spore is a subterranean mass of tissue of considerable size and bears both the male and female organs (antheridium and archegonia).

• However, it is more common that they are distributed vegetatively through above or below ground rhizomes.

Lycopodium life cycle

Selaginella

• Spike Mosses • Especially abundant in tropics.• Branch more freely than ground

pines.• Leaves have a ligule on upper

surface. • Produce two different kinds of

spores and gametophytes (heterospory).

Selaginella life cycle

Strobili

Selaginella

Cross section of the Selaginella stem

Selaginella

Cross section of strobili

Selaginella

Microsporangium and Megasporangia

Selaginella

Cross section of strobili

Phylum Sphenophyta

• Horsetails or Scouring rushes• Look like horsetails and contain silica

that helped to scour dishes and utensils.

• Ancient members were tree sized, today, they grow only to a maximum of 1 m.

• Sphenophytes have jointed stems Equisetum

Phylum Sphenophyta

• Leaves form strobillus at the tips of some stems

• Most grow in marshes, stream banks; damp soil

• Some grow in fields, roadsides; in drier areas

• Reproduction very similar to lycophytes.

Phylum Sphenophyta• The plant is essentially stem, it has a rhizome

which puts out adventitious roots. • The leaves are a whorl of non-photosynthetic

scales at each node. Some species produce lots of feathery branches.

• Their cell walls contain silica which makes the stems coarse textured, and led to their use as a natural scouring pad for cook ware.

• Spores are produced in strobili and although the plant is homosporous the gametophytes are unisexual.

Phylum Sphenophyta

Equisetum life cycle

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