Biodiversity (reproduction)

Algae (Spirogyra)



Phylum : Bryophyta Class : Hepaticae Example : Marchantia





Phylum :  Bryophyta  Class : Musci  Example :  Funaria

 
fungi (mucor) structure



Phylum : Pteridophyta / Filicinophyta Class : Filicinae Example : Dryopteris (Fern)






Phylum : Coniferophyta Example : Pinus





Phylum : Angiospermatophyta Example : Caesalpinia


Generally dioecious plants have both the male and female reproductive organs on separate individuals of the same species while monoecious plants have separate male and female flowers on the same plant.


Futher explaination

Male flowers are those whose gametes (pollen) leave the flower, while female flowers are those whose gametes (ova) remain in the flower and are receptive to the male gamete.


Monoecious plants have the 2 sexes on the same plant, with all individuals producing male pollen and female eggs and seed. Monoeciousness is the norm in most plants of the world.
Some monoecious plants can be classed as hermaphrodite with flowers which contain both male and female parts.
In many hermaphrodite flowers there is a time when the flower is male with anthers distributing pollen, and a time when they are female, with a receptive stigma. By timing their sex expression the plant increases the likelihood of being pollinated by another member of the same species. The pollen would not be shed when the ovary was ripe. Usually the female stigma is receptive after the pollen is shed.  Outcropping or fertilization by another member of the same species is encouraged, which enhances variety within the species
Monoecious plants have separate male and female flowers found on the same plant. The same idea of timing the male and female functions to maximize the chance of cross pollination occurs but the likelihood of self pollination is increased.


Dioecious plants have male and female flowers on separate plants. Exotic plants that this occurs in include Kiwi fruit and Cannabis sativa which have male and female plants. A characteristic of the The New Zealand flora is the high % of plants that have the sexes on separate plants (dioecious). Approx 12-13% of our flora are dioecious. (Britain 2-5%, South Australia, 3.9%., Hawaii 5%). However in any plant association there may be up to 50% of the individuals who exhibit dioeciousness
The significance of dioeciousness  to the propagator of seeds is that female plants need to be sourced if seed is to be collected.
Dioeciousness of plants account for the variability in seeding from year to year that some species exhibit because seeding will be determined by synchronising the time at which the male and female parts are functional. Rimu may go 7-12 years before seed on females is produced in abundance. These years are termed mast years.
As a male tree may be some distance from a female tree, the environmental conditions that determine flowering would be more variable in separate trees than the same tree. There is more likelihood of reproductive failure if the nearest tree of the opposite sex is some distance away. The fact that pollen from a distant tree must fertilise a female tree may put the successful reproduction and production of viable seed under stress. Logging of a population, and a reduction in total density of the adult trees and total gamete production will reduce the likelihood of fertilisation . This seems to be the case in Monoao( Dacrydium kirkii), a dioecious species of conifer that grows in Northlands kauiri forests.Monoao has become relatively rare in the wild with its natural range vastly reduced to remnant populations in Coromandel, Northland and Little Barrier Island