(i) Protonema:
The predominant stage of the life cycle of a moss is the gametophyte which consists of two stages. The first stage is protonema stage, which develops directly from a spore. It is a creeping green branched form frequently a filamentous stage.
(ii) Antheridium:
Antheridium is a haploid structure producing and containing male garnets. Antheridium is the male sex organs of lower plants such as pteridophytes, bryophytes etc., Antheridium produces antherozoids. These antherozoids are released into surrounding such that they come in contact with female sex organs (archegonium)
(iii) Archegonium:
Archegonium is a multicellular organ of gametophyte phase of certain lower plants. It produces and contains Ovum or female gametophyte. Archegonium is a female sex organ. Archegonium is present on surface of the plant thallus. Archegonium is flask shaped. When Antherozoids come in contact with eggs in Archegonium they form Zygotes.
(iv) diplontic:
Type of life cycle in plants where diploid sporophyte is dominant, photosynthetic independent phase of the plant. The gametophytic phase is represented by the single to few-called haploid gametophyte. All seedbearing plants (gymnosperms and argiosperms) follow this pattern.
(v) sporophyll:
In pteridophytes main plant body is sporophyte. The sporophytes bear sporangia that are subtended by leaf-like appendages called sporophylls. In some cases sporophylls may form distinct compact structures called strobili or cones. The sporangia germinate to give rise to inconspicuous, small but multicellular prothallus.
(vi) isogamy:
Isogamy refers to form of sexual reproduction involving two gamets similar in size and appearance. Chiamydomonas’s gametes have same size and are flagellated Spirogyra’s gametes are similar in size but don’t have flagella.
