Bryophyte umbrellas !
When a bryophyte spore settles somewhere, it sprouts and grows into a gametophyte. This then is egg and sperm producing plant. It is this stage we mostly see as green.
This attached plant is green and leafy, but usually very small. Commonly called liverworts, their reproductive organs (eggs and sperm) are found inside capsules which look like little umbrellas sticking up from the plant. Antheridia make sperm and archegonia make eggs.
When it’s raining, the eggs stay under their umbrella but the sperm take a free ride on the rainwater down one umbrella and up the next to seek out eggs.
The fertilized eggs develops and grows into a sporophyte. This spore producing plant stays connected. It looks like a capsule on top of the gametophyte on a long slender stalk. It divides and makes spores of the same size and type (homosporus).
LYCOPODS (club mosses and quillworts)
Just like the Bryophytes, If a spore finds a suitable habitat, it can grow into a gametophyte. However, the lycopod gametophyte grows in close association with fungi. Just like in the Bryophyte they produce homogeneous (all the same) spores which germinate and grow into adults.
Heterosporous (sexually distinct spores) plants, such as these, produce spores of two sizes. One larger megaspore in effect functioning as a “female” and the smaller microspore as a “male”. After fertilization, the sporophyte grows out of the top of the gametophyte, so it looks like a headdress of some kind.
We LOVE Selaginella !
The leafy part is the gametophyte, the tall spindle on top is the sporophyte.
Ferns also do not produce floral parts. Here the spores are produced and released from the underside of leaves or from special spore producing stems. The spores land on moist soil and germinate into a secondary type of plant called a gametophyte. It is usually very small (1”) and flat. This plant in turn produce both eggs and sperm which when fertilized form a new plant. This new plant grows off the gametophyte until it becomes an adult spore producer that we know as a fern.
Spores in clusters on back of fern leaf.
Fern life cycle – adult gametophyte with new baby sporophyte attached.
PRIMITIVE SEED PLANTS
The most primitive reproductive parts of plants where formed in species which evolved million of years ago in the Devonian period. These formed simple precursors to modern floral parts. Cormo rhynia is such an example. It retains the seed in an uncovered pod or cone.
CONE BEARING SEED PLANTS
Between the arrival of modern flowering plants, but after bryophytes and ferns are several groups of plant that are also considered primitive. The cone bearing plants (conifers and cycads). The cone partially encloses the seed.
Cycads are also considered primitive, but in a class apart from other cone bearing plants.
Typical cone producing plant cycle
Primitive (and toxic !!!) Cycads are mainly used outdoors as a foliage plant in a warm weather climate. They are sometimes used as indoor plants as well. Seeds are poisonous.
Male cones on Cycad.
Female cones with exposed seeds.
True flowering plants only begin with the Ceratophyllales (still much older than Methuselah) then followed by the Magnoliales. They tend to be trees and Dicotyledons. Their seeds are totally covered and protected. They are also mostly extinct!
Primitive flowers that are currently alive on the planet tend to be large, simple, flat, multi stamen flowers. They are wind pollinated and with few or no secondary floral parts. An example of this is Magnolia.
Magnolias evolved in a world with few insects!
Their pollination choice was wind so the flower never became specialized – no need for color, fragrance or different floral parts to attract insects for pollination.
Ask one of our garden experts to plant some primitive Magnolias for you !
Star magnolia is my favorite!
If you want some in your garden – Call Plant Specialists TODAY !
We have experts that know which will grow in your garden
– and we can care for them as well !
Don’t delay – the sooner the better !
GREENING NEW YORK FOR OVER 51 YEARS !
Article written by our Staff Horticulturist, Peter B Morris, BSc, MSc, MBA
All photographs used with permission @SHUTTERSTOCK