140 



KINGDOMS MONERA AND PROTISTA: 



multicellular species. The more conspicuous forms 

 usually are called slime molds, molds, smuts, rusts, 

 puffballs, earthstars, or mushrooms. These generally 

 are discovered growing upon plants or organic re- 

 mains on the ground. However, one should recognize 

 more groups for adequate appreciation of the taxon 

 (see below). 



This is a cosmopolitan subkingdom and certain in- 

 dividuals also approach a world-wide distribution. 

 They can be found in salt and fresh water, in moist 

 areas, and in soil. Many occur as external or internal 

 parasites. The only serious restrictions on their 

 distribution are temperature and moisture. At 

 temperatures over 86°F most cease growth. Opti- 

 mum functions usually occur between 68° and 79°F. 

 Also, some moisture is required for them to com- 

 plete their life cycles. In spite of this, they occur in 

 arctic and desert areas but appear to be less abun- 

 dant in these environmental extremes. 



These organisms contain no chlorophyll and most 

 definitely are consumers rather than producers of 

 nutrients. Their main ecological roles are sapro- 

 phytic, breaking down organic remains, or parasitic, 

 often causing mild reactions, disease, or even death 

 to their hosts. Parasitic fungi apparently infest all 

 major taxa, but most parasites also can live upon or- 

 ganic remains. Therefore, their function in any com- 

 munity is allied to that of other organisms with 

 heterotrophic nutrition. 



In addition to some being associated with certain 

 blue-green or green algae as lichens, other fungi 

 form a mycorrhiza association with higher plant roots. 

 Fungi filament penetration of root cells {but only the 

 surface layer) is a fundamental part of this associa- 

 tion. In some cases at least, it appears that the as- 

 sociation enables transfer of certain soil nutrients to 

 the plants and that plant cells digest and gain 

 nutrients from fungal filaments. Also, it seems that 

 fungi filaments gain nutrients from the plant roots. 

 Therefore, on occasion, the relationship might be 

 beneficial to both participants; but in other cases 

 the fungus acts like a parasite. 



Due to their saprophytic activities, they may de- 

 stroy man's stored goods, especially food. Also, they 

 are agents of most known plant diseases, especially 

 various blights, mildews, wilts, scabs, blunts, rusts, 

 and smuts. Fungi cause some potentially fatal 

 diseases in man but are better known as agents of 

 skin infections like ring worm and athlete's foot. 

 However, as a group, they are extremely beneficial 



They produce various chemicals important as drugs 

 (e.g., penicillin and cortisone), vitamins, enzymes, 

 baking and brewing agents, and cheese-producing 

 materials (e.g., chemicals that form blue and other 

 cheeses). The larger fleshy fungi, mushrooms in- 

 cluding truffles and puflfballs, are human food. Also, 

 the fungi provide biologists with many clues as to the 

 basic workings of life processes. 



CLASS PHYCOMYCETES (Algal Fungi) 



Diagnosis: filament mass (mycelium), when pres- 

 ent, is without cross structures separating nuclei, 

 except where reproductive structures are formed; 

 without fruiting bodies; most produce both sexual 

 and asexual spores in sporangia; sporangia are ab- 

 sent in other true fungi; sporangia often con- 

 tribute distinctive specks to mycelia; sporangia 

 sexual spores possess no, one, or two flagellae; 

 flagellae absent in other true fungi (Figure 8.10). 



ALGAL FUNGI 



^So 



water mold on aquatic 

 object 





white rusij milk-white 

 powder in clusters on 

 plant, plant interior 

 brownish (spores) 



black mold, dark specks 

 (sporangia) on gray to 

 black mold, saprophytic 

 and parasitic 



fly fungus, a moldy 

 insect parasite 



Figure 8.10 Conspicuous algal fungi, about natural size. 



Structure: unicellular forms without a filament 

 mass (the entire cell commonly transforming to the 

 next stage), but either with a few anchoring struc- 

 tures, or with a much abbreviated mycelium; fila- 

 mentous forms possess a true mycelium of branching 

 hyphae; visible structures normally are powdery or 

 moldy appearing; no fruiting bodies produced. 



