Encyclopedia of Environmental Science and Engineering, Volume I and II

MICROBIOLOGY 689

microscopic and macroscopic and macroscopic groups. In

general, they have rigid cell walls, lack chlorophyll, and are

usually immotile. Most fungi reproduce asexually or sexu-

ally by means of spores though important budding groups

such as yeasts are well known. Since fungi are classifi ed by

the pattern of their sexual structures, fungi whose sexual

stages are unknown are placed into a group called Fungi

Imperfecti and assigned genera on the basis of their asexual

structures. They are further subdivided into the so-called

lower and higher fungi. The lower fungi, Phycomycetes, are

also called water molds but not all are aquatic (e.g. black

bread molds). Some species multiply by means of fl agellated

gametes or fl agellated spores i.e. more like certain green

algae than other fungi; Most, but not all, Phycomycetes have

COCCI BACILLI

VIBRIOS SPIRILLA

SPIROCHAETES ACTINOMYCETALES

(A) MORPHOLOGICAL CHARACTERIZATION OF BACTERIA

(B)

(C)

FIGURE 3 A. General morphological characteristics of bacteria; B. Variety of morphological types among the

cocci; C. Variety of morphological types among the bacilli (rods).

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