Phylum Thallophyta - The Algae - Archimycetes
The Archimycetes are Fungi devoid of a mycelium, the body of the organism consisting of a ~aked mass of cytoplasm termed a plasmodium, which finally, after a period of vegetative growth, becomes converted into one or more sporangia. These sporangia may be simple or elaborate structures containing a large number of spores. The spores on germination give rise to motile swarm cells which function as gametes, fuse in pairs and produce a fresh vegetative plasmodium.
The organisms may be saprophytic or parasitic and are quite common.
They probably represent primitive groups of organisms which have not contributed anything to the evolution of the main groups of the Fungi but are rather side lines which have not proyed specially successful, but \yhich still exist to the present day as survivals of an early type of fungal organization.
The limits of this group have been yariously held by different authors to include a greater or smaller number of orders of the lo\yer Fungi. Possibly the simplest, though not necessarily the most correct view, is to consider the Archimycetes as embracing three orders, all of which must be regarded as side lines in evolution, while placing the only order which appears to have contributed to the higher Fungi, namely the Chytridiales, in the Phycomycetes.
According to this scheme we are left with three orders :-
- Myxomycetales , sometimes called the Mycetozoa, which are saprophytes.
- Acrasiales , in which the plasmodia readily fragment into separate amoeboid cells and which live as saprophytes on dung.
- Plasmodiophorales , which are parasites of higher plants.
Myxomycetales : Next>>
