TAXONOMY 247 



Rhodymenia palmata or Irish Dulse is a purplish-red, flat, mem- 

 branous, palmately cleft or dichotomous red alga growing on the 

 tissues of other algae along northern shores of the Atlantic between 

 the low- and high-tide marks. 



SUBDIVISION IV FUNGI 



This great assemblage of thallophytes is characterized by the total 

 absence of chlorophyll and so its members possess no independent 

 power of manufacturing food materials such as starches, sugars, etc., 

 from CC>2 and H 2 O. Consequently they are either parasites, depend- 

 ing for their nourishment upon other living plants or animals, called 

 hosts] or saprophytes, depending upon decaying animal or vegetable 

 matter in solution. Some forms are able to live either as saprophytes 

 or parasites while others are restricted to either the parasitic or 

 saprophytic habit. The vegetative body of a fungus is known as a 

 mycelium. It consists of interlacing and branching filaments 

 called hypha, which ramify through decaying matter or invade the 

 tissues of living organisms and derive nourishment therefrom. In 

 the cases of parasites, the absorbing connections which are more or 

 less specialized and definite are called haustoria. In the higher forms 

 the hyphae become consolidated into false tissues, and assume definite 

 shapes according to the species. Of this character are the fructi- 

 fying organs which constitute the above ground parts of Puff Balls, 

 Cup Fungi, Mushrooms, etc. There are four classes of Fungi, viz. : 

 Phycomycetes, Ascomycetes, Basidiomycetes and Fungi Imperfecti. 



CLASS I. PHYCOMYCETES, OR ALGA-LIKE FUNGI 



The Phycomycetes represent a small group of fungi showing close 

 affinity with the green algae. Their mycelium is composed of cceno- 

 cytic hyphae, which suggests a close relation with the Siphonales 

 group of green algae. Their sexual organs are likewise similar in 

 structure. Transverse septa appear upon the formation of repro- 

 ductive organs separating these structures from the vegetative 

 hyphae. 



