branched with simple septum. • Majority of them are saprophytes but few parasites are also known (Powdery mildew – Erysiphe ). penultimate cell of the hypha fuse to form a diploid nucleus. This cell forms young ascus.
• The diploid nucleus undergo meiotic division to produce four haploid nuclei, which further divide mitotically to form eight nuclei. The nucleus gets organised into ascospores. • The ascospores are found inside a bag like structure called ascus. Due to the presence of ascus, this group is popularly called "Sac fungi".
• Asci gets surrounded by sterile hyphae forming fruit body called ascocarp. • There are types of ascocarps namely Cleistothecium (Completely closed), Perithecium (Flask shaped with ostiole), Apothecium (Cup shaped, open type) and Pseudothecium . Basidiomycetes • Basidiomycetes include puff balls, toad stools, Bird’s nest fungi, Bracket fungi, stink horns, rusts and smuts (Figure . ).
(b) Dolipore septum Nucleus (c) Clamp connection (a) Geaster Figure . : Structure and Reproduction in Basidiomycetes • The members are terrestrial and lead a saprophytic and parasitic mode of life. (a) Peziza (b) Cleistothecium Ascus Paraphysis Ascospore Ostiole Ascus Paraphysis Ascospore (c) V.S. of Perithecium (d) V.S.
of Apothecium Ascospore (e) Steps involved in the development of Ascus Figure . : Structure and reproduction in Ascomycetes • Asexual reproduction takes place by fission, budding, oidia, conidia, and chlamydospore. • Sexual reproduction takes place by the fusion of two compatible nuclei. • Plasmogamy is not immediately followed by karyogamy, instead a dikaryotic condition is prolonged for several generations.
• A special hyphae called ascogenous hyphae is formed. • A crozier is formed when the tip of the ascogenous hyphae recurves forming a hooked cell. The two nuclei in the • The mycelium is well developed, septate with dolipore septum(bracket like). Three types of mycelium namely primary (Monokaryotic), secondary (Dikaryotic) and tertiary are found.
• Clamp connections are formed to maintain dikaryotic condition. • Asexual reproduction is by means of conidia, oidia or budding. • Sexual reproduction is present but sex organs are absent. Somatogamy or