8 



ALG.E. 



Tan (Fuligo septicd) has a fruit-body composed of many sporangia 

 (an yEthalium), which has the appearance of flat, irregular, brown 

 cakes, inside the fragile external layer of which a loose powder, 

 the spores, is found. It generally occurs on heaps of tanners' bark, 

 and appears sometimes in hot-beds in which that material is used, 

 and is destructive by spreading itself over the young plants and 

 choking them. 



All the motile stages may pass into resting stages, the small forms 

 only surrounding themselves with a wall, but the large ones at the 

 same time divide in addition into polyhedral cells. When favour- 

 able conditions arise, the walls dissolve and the whole appears 

 again as a naked (free-moving) mass of protoplasm. 



To the genuine Slime-Fungi belong : Arcyria, Trichia, Didymium, 

 Physarum, Stemonitis, Lycogala, Fuligo, Spumaria, Reticularia. 



Some genera wanting a sporangium- wall belong to the Slime- 

 Fungi : Ceratiomyxa, whose fruit-body consists of polygonal 

 plates, each bearing stalked spores ; Dictyostelium, in which the 

 swarm-stage is wanting and which has stalked spores. Plas- 

 modiophora brassicce preys upon the roots of cabbages and other 

 cruciferous plants, causing- large swellings. PL alni causes 

 coral-shaped outgrowths on the roots of the Alder (Altius). 

 Phytomysea Jeguminosariim may be found in small knobs (tubercles) 

 on the roots of leguminous plants. It is still uncertain whether 

 it is this Fungus or Bacteria which is the cause of the formation 

 of these tubercles. 



Sub-Division II. ALG/E. 



Mode of Life. The Algte (except most of the Bacteria) are 

 themselves able to form their organic material by the splitting 

 up of the carbonic acid contained in the water, or air in some 

 cases, and for this purpose need light. The majority live in 

 water, fresh or salt, but many are present on damp soil, stones, 

 bark of trees, etc. 



With the exception of the Bacteria, no saprophytes have actually 

 been determined to belong to this group, and only very few 

 true parasites (for instance, Phyllosiphon arisari, Mycoidea, etc.), 

 but a good many are found epiphytic or endophytic on other Alga?, 

 or water plants, and on animals (for instance, certain Schizophycece 

 and Protocnccoidece ; Trichopliilus ivelckeri in the hairs of Bradypus, 

 the Sloth), and several species in symbiotic relation to various 



