Division Bryophyta: Mosses and Their Allies Thalloid Liverworts Moss Gametophytes with sporophytes evident
Golden Bog Moss (Sphagnum) Hornwort (Anthoceros)
Division Bryophyta – Nonvascular PlantsI.Characteristics and General Life Cycle of BryophytesA. Bryophytes lack well developed vascular tissue (xylem and phloem).B. Bryophytes lack true roots and leaves.C. Bryophytes have Rhizoids for anchorage. D. Bryophytes absorb their water and nutrients at the soil’s surface.
E. Bryophytes have two stages in the life cycle 1. Gametophyte– the dominant haploid stage in the life cycle, usually associated with mycorrhizalfungi. These have gametes. a. Antheridia(singularly antheridium) maleorgan which produces many flagellated sperm asgametes. b. Archegonia(singularly archegonium) femaleorgans which each produce only one egg as agamete.
2.Sporophyte – the short-lived, unbrancheddiploid stage in the life cycle of the Bryophytes. It contains a terminal sporangium, which produces spores that explode from the sporophyte, (known as a calyptra). This sporophyte releases spores which grow into protonema that develop into new gametophytes.
II. Bryophytes and their Diversity • Mosses • 1.Mosses do not have leaves but do have leafy extensions. • 2.Their spores form a filamentous protonema. (means first thread) • 3.The protonema sends out shoots which grow up into gametophytes. These gametophytes could be unisexual (dioecious) or bisexual (monoecious).
4.From the gametophyte arises a diploid sporophytethat produces a single capsule known as the calyptra, a structure that protects the developing spores from dessication. The mature sporophyte has three parts, the foot, the seta and the capsule. • 5.The capsule is a sporangium for the development of spores.
B. Liverworts • Liverworts were named in medieval times during the era of human discovery. Since they were lobed they were thought to be similar to the human liver. • They always have unicellular rhizoids. • They have photosynthetic uppersidesand nonphotosynthetic undersides. • Their sporangia are often unstalked. • They shed spores from the sporangia. • They reproduce asexually using gemmules or ‘splash cups’, that survive as the “older” plant dies off. • The most common species is Marchantia.
Marchantia sporophytes gametophytes
C. Hornworts • Hornworts are our smallest group of bryophytes with only 100 species. • The most common and well known is called Anthoceros. • The sporophyte is shaped like a small horn. • Each photosynthetic cell has only ONE chloroplast. • The cavities of hornworts are filled with mucilage.
D. Ecologies and Distribution • Peat moss is used widely as a fuel source and as a preservative. • Peat bogs have a very high acidic pH, which enables it to preserve dying organisms such as Lindow Man. • Mosses are used to: • a. stuff furniture • b. absorb oil spills • c. protect in the transportation of living plants • d.Sphagnum has been used by native peoples as a diaper and as a disinfectant, because of its high acidity. • e. Sphagnum was used by soldiers in the British army in WWI to treat wounds.