[Music] forests are dominated by large plants that crowd one another in their competition for light but Far Below in the forest floor there's a group of tiny plants known as the Mosses with over 10,000 species these plants thrive in many habitats these moss plants form gamits and are therefore gites [Music] mosites are hloy containing only one set of chromosomes their small and compact form enables the stems to stay upright while riseo anchor them to the soil moist easily accumulates around the densely spaced stems this often leaves a film of water on the leaves and on the stem [Music] tip hairlike growths called pareses help to hold the water around the stem [Music] tips some stem tips are male and contain reproductive structures called antheridia These are complex organs consisting of many cells each is supported by a [Music] St the upper portion consists of an outer protective jacket that surrounds a group of sperm [Music] cells at the tip of a female plant there are numerous reproductive structures known as aragonia the top of each consists of a Slender neck the middle region contains a chamber called the Venta the base of the aronium is ATT attached to the Moss stem by a stalk an egg cell is formed inside the [Music] Venter inside the neck the breakdown of cells forms a central Canal containing sperm attractant [Music] a rain Shar provides the ideal conditions for sperm release and their transfer to a female plant droplets of rain water collect at the tips of the Moss stems inside the drop of water at the tip of the male stem the antheridia open this releases cells containing firm which float up to the surface raindrops flash some of this water out of the male plant some Splash drops contain sperm cells and fall onto the tip of a female [Music] stem the sperm now escaped from their surrounding membrane and use their fagella to move about in search of an egg [Music] the aronium now opens and releases a sperm [Music] attractant the sperm swim towards the source of the attractant and into the opening once inside they are guided down to the egg [Music] the first sperm to arrive enters the egg [Music] cell fertilization is completed with a sperm and egg nuclei fuse creating a diploid zygote [Music] after fertilization many changes take place on the female stem tip at first the zygote remains within the Venta where it forms an embryo however one end of the embryo soon grows out of the Venta and into the female stem this allows it to obtain water and nutrients from the female plant the other end of the embryo grows upward the ventor expands to accommodate this growth but eventually it is split in half the embryo now forms a very long stalk or CA that lifts the top half of the ventor up into the air this results in a small deployed plant the sporify attached to the tip of the female stem [Music] these female stems have all been fertilized and support spites above them the tip of each is covered by the torn Venta or calypter this soon Falls away exposing a capsu or sporangium the capsule contains fertile tissue consisting of [Music] spites inside the nucleus of each sparite there are two sets of chromosomes the nucleus divides by the process of meiosis forming four haid [Music] nuclei thin w now form around each nucleus resulting in a cluster of four cells known as the [Music] tetrad a deposit of spolin produces cells with thick resistant walls called spores as the spores are forming the capsule dries out and hardens soon The liboro percum Falls away way revealing a ring of fine teeth called the perone these surround an opening in the capsule as they dry out they Bend backwards allowing the spores to escape a light Breeze is all it takes to carry the spores away from the parent plant [Music] spores carried by the wind May land on an exposed Surface after rain the Spore cell absorbs water and germinates but instead of growing into a new moss plant it forms a branch filamentous protonema however after a period of growth some of the protonema form buns each Bud will proceed to grow into a new leafy gight spores then enable mosses to spread and colonize new areas often some distance from the parent plant using both gametes and spores these unassuming members of the plant kingdom quietly proceed to thrive and multiply they have successfully spread from polar regions to the tropics and are equally at home in our cities or in the countryside perhaps a key to their success is their small size Perhaps it is due to their ancient linear AG going back more than 400 million years to a time when plants were first colonizing the land whatever the reason these tough K attractive opportunists hold many surprises for the interested Observer