SPORE BEARING PLANTS: THE LOWER VASCULAR PLANTS

KINGDOM PLANTAE

Bryophytes Tracheophytes (mosses- non-vascular plants) (vascular plants) HIGHER VASCULAR PLANTS LOWER VASCULAR PLANTS (with megaphylls) (with microphylls) Div. Psilophyta -Psilotum Pterophytes Spermatophytes Div. Lycophyta (spore bearing) (seed bearing) -Lycopodium FERNS -Selaginella -Nephrolepis Div. Arthrophyta -Equisetum Gymnosperms Angiosperms (naked seed) (with fruits) Div. Cycadophyta Div. Magnoliophyta -Cycas revolute -Cycas circinalis Div. Pinophyta -Pinus kesiya -Pinus insularis LVPs or lower vascular plants (FERN ALLIES) General characteristics:

a. simple vascular tissues b. diplo-haplantic life cycle – alternating sporophyte (2n) and

gametophyte (n) generations.

c. Sporophyte (bigger/ more dominant) and gametophyte (smaller) are INDEPENDENT.

d. Sporophyte is dichotomously branched. e. With simple “leaf-like” appendages (microphylls)

I. Psilophyta: Psilotum or whisk fern

- lacks true roots and leaves - with rhizomes-branched underground stem - with rhizoids – function for anchorage and absorption - with ENATIONS – small scale-like epidermal outgrowths; no veins - HOMOSPOROUS- (one type of spores) borne in a 3 clustered sporangia-

--- SYNANGIUM. - EXOSPORIC gametophyte germination (outside the spores) - With bisexual gametophytes that are underground; with ANTHERIDIA

and ARCHEGONIA. - Type of stele: PROTOSTELE.

II. Lycophyta

A. Lycopodium or club mosses

- with rhizome and true roots

- with MICROPHYLLS – small leaf-like structures - HOMOSPOROUS – organized in a STROBILUS

(collection of sporophylls bearing sporangia) *sporophyll is a fertile microphyll

- EXOSPORIC gametophyte germination - With bisexual gametophytes that underground - Type of stele: ACTINOSTELE (star-shaped

protostele)

B. Selaginella or ground pines

- with rhizome and true roots; presence of RHIZOPHORES (support roots arising from the stem)

- with MICROPHYLLS - HETEROSPOROUS (two types of spores) – organized

into a strobilus - ENDOSPORIC gametophyte germination

(gametophyte develops within the spores-sporangial wall.)

- With UNISEXUAL gametophyte - Type of stele: POLYSTELE (3 sets of concentric

amphicribral)

strobilus

microphyll

Sporophyll

Sporangium

Spores

Megasporophyll

Megasporangium

Megaspore

Microsporophyll

Microspores

Microsporangium

Rhizophore

III. Arthrophyta: Equisetum or horsetail

- with true roots, stems, and leaves - with MICROPHYLL-like projections at the joints of the stem - HOMOSPOROUS – spores with ELATERS (strap-like structures that

uncoil upon absorption of water; to facilitate spore dispersal) - Sporangia borne in a STROBILUS; with margins of umbrella-like

structures (SPORANGIOPHORE) - EXOSPORIC - Type of stele: ARTHROSTELE (modified eustele; with system of

canals)

strobilus

SPORE BEARING PLANTS: THE HIGHER VASCULAR PLANTS DIV PTEROPHYTA: Ferns -similar characteristics with LVPs: reproduce by spores (HOMOSPOROUS) : independent gametophyte : EXOSPORIC germination of gametophyte :bisexual gametophyte -2nd largest group; one of the most diverse -fern sporophyte: parts

Nephrolepis

-fern gametophyte: parts

Prothallus A-young sporophyte; B-gametophyte

Adiantum

Asplenium

SEED BEARING PLANTS: THE HIGHER VASCULAR PLANTS SPERMATOPHYTES General characteristics: -reproduce by seeds -gametophyte dependent on sporophyte -HETEROSPOROUS -ENDOSPORIC -unisexual gametophyte GYMNOSPERMS -NO OVARY: EXPOSED OVULE: NAKED SEEDS DIV. CYCADOPHYTA: Cycads (Cycas circinalis, Cycas revoluta) -dioecious -megasporophyll – loose clusters microsporophyll – strobilus --- microsporangia with pollen grains

Cycas circinalis

(sporophyte)

DIV. PINOPHYTA: Pines (Pinus kesiya, Pinus insularis) -monoecious -staminate cone/ androstrobilus –microspores--- winged pollen grains ovulate cone/ gynostrobilus- ovuliferous scales and ovules (seeds)

Male cone winged pollen grain

Female cone

megasporophyll

ovule

male

strobilus