Modification of Mycelium or Thallus
Rhizomorphs:
Rhizomorphs are thick stands of mycelium which aggregated longitudinally in varying degrees of complexity in such way to form complex tissue in which hyphae losses their individually. Hyphal thread can not be distinguished. They can grow in soil as well as trunks the trees. They can withstand unfavourable conditions. They belongs to subdivision Basidiomycotina. E.g. Arnillaria millea
Stroma or Stromata:
It is a compact mass of the hyphae and appears as pseudoparenchymatous tissue and contain fruiting body of the fungus. E.g. Ergot of Bajara.
Sclerotium or Sclerotia:
Sclerotia is the modified forms of vegetative mycelium , which forms compact mass of the hyphae, becomes hard and acts as resting body which is resistant to unfavourable conditions. It may remain dormant for long periods and germinate under favourable conditions.
E.g. Sclerotium spp.
Dormant Mycelium:
It is the mycelium which hibernates in the host tissue to tide over unfavourable conditions, if remains in a dormant condition for a part of its life cycle and come up into activity when conditions are favourable.
E.g. Downey Mildew of Grape, Loose smut of wheat, Koleroga of Arecanut.
Gemmae:
These are the chamyfospores produced in lower fungi whose walls are thinner. They occur either singly or in chains a becomes separated after maturing. Gemmae break free from the mycelium and disperse in water. E.g. Mucor sp, Saprolegnia sp.