600 FUNGI IMPERFECT!: THE IMPERFECT FUNGI 



folds and eventually became stromatic structures containing pycnidial 

 cavities. Montemartini (1899) reported similar observations in several 

 groups of Imperfect Fungi. Tuhercularia (Hyalosporae) forms rounded, 

 bright-colored cushions, mostly on wood or bark. They are covered by 

 fine, branching conidiophores bearing singly at the tips of the branches 

 the small, ellipsoidal hyaline conidia. T. vulgaris Tode is the imperfect 

 stage of Nectria (Creonedria) cinnabarina (Tode) Fr. Volutella (Hyalo- 

 sporae) produces its small, almost spherical sporodochia on the leaves or 

 stems of herbaceous plants. Each sporodochium is surrounded by a circle 

 of long bristles. The conidiophores are mostly unbranched. Several species 

 cause diseases of plants. V. dianthi (Hals.) Atk. causes cankers near the 

 base of the stem of carnation {Dianthus caryophyllinus L.) which ulti- 

 mately kill the plant. 



Fusarium (Hyalophragmiae) produces its usually lunate conidia on 

 rather broad, indefinitely bordered sporodochia as well as singly on the 

 mycelium. The conidia are usually produced in a mass of slime and in mass 

 may be white, yellow, orange, or red in color. The many hundred forms 

 are distinguishable with difficulty, requiring to be cultured on a variety of 

 culture media, under standard conditions of environment. In addition to 

 this type of conidia (macrospores) there may be produced microspqres 

 which are rounded or short ellipsoid conidia, in heads (Cephalosporium 

 type), as w^ell as spores intermediate in character. Chlamydospores are 

 often produced in abundance in the mycelium. Sometimes one or two are 

 formed in a macrospore. Many species of Fusarium produce pigments 

 which are of assistance in distinguishing the species. Among the species of 

 this genus are many that cause wilt diseases. The nomenclature of the 

 different wilt-producers in this genus is very much in dispute. The fact 

 that on the one hand forms culturally and morphologically indistinguish- 

 able may be limited to distinct, unrelated hosts, and that on the other 

 hand wilt may be caused in one host by forms culturally and morphologi- 

 cally quite different makes the assignment of names to these fungi difficult. 

 All wilt-producing species of Fusaria are capable of growing saprophyti- 

 cally in the soil for many years, and from the same lot of soil may usually 

 be isolated several forms that are distinguishable in structure, habits in 

 culture, and pathogenicity. In some forms sporodochia appear only very 

 rarely if at all in culture. It is only a very artificial classification to place 

 the genus in the Tuberculariaceae. Wilt diseases are produced by various 

 strains oi Fusarium in tomato {Lycopersicon esculentum Mill.), flax {Linum 

 usitatissimum L.), cotton (various species of Gossypium), watermelon 

 (Citrullus vulgaris Schrad.), cowpea {Vigna sinensis Endl.), potato 

 (Solanum tuberosum L.), celery {Apium graveolens L.), and many other 

 important crops. Fusarium-Yike fungi are known as the imperfect stages 

 of Gibberella zeae (Schw.) Fetch, and of various other Hypocreales. 



Among the dark-spored members of this form family is the genus 



