50 



PLANT STRUCTDRES 



From the hyphal threads composing the mycelium verti- 

 cal ascending branches arise, which are set apart to produce 

 the asexual spores, which are scattered and produce new 

 mycelia. These branches are called ascending liyplm or 

 sjuirophores, meaning " spore bearers." 



Sometimes, especially in the case of parasites, special 

 descending branches are formed, which penetrate the sub- 

 stratum or host and absorb the food material. These spe- 

 cial absorbing branches are called haustoria, meaning " ab- 

 sorbers." 



Such a mycelial body, with its sporophores, and perhaps 

 haustoria, lies either upon or within a dead substratum in 

 the case of saprophytes, or upon or within a living plant or 

 animal in the case of parasites. 



38. The siibdivisions. — The classification of Fungi is in 

 confusion on account of lack of knowledge. They are so 

 much modified by their peculiar life habits that they have 

 lost or disguised the structures which prove most helpful in 

 classification among the Algae. Four groups will be pre- 

 sented, often made to include all the Fungi, but doubtless 

 they are insufificient and more or less unnatural. 



The constant termination of the group names is mycetes^ 

 a Greek word meaning " fungi." The prefix in each case is 

 intended to indicate some important character of the group. 

 The names of the four groups to be presented are as follows ; 

 (1) Pliycomycetes ("Alga-Fungi"), referring to the fact 

 that the forms plainly resemble the Algse ; (2) Ascomycetes 

 ("Ascus-Fungi"); (3) ^cidiomycetes ("^cidium-Fungi ") ; 

 (4) Basidiomycetes (" Basidium-Fungi "). Just what the 

 prefixes ascus, cecidium, and hasidium mean will be ex- 

 plained in connection with the groups. The last three 

 groups are often associated together under the name My- 

 comycetes^ meaning " Fungus-Fungi," to distinguish them 

 from the Phycomycetes, or " Alga-Fungi," referring to the 

 fact that they do not resemble the Algae, and are only like 

 themselves. 



