1 86 



DIVISION II. COURSE OF DEVELOPMENT OF FUNGI. 



The sporocarps are formed and borne in some species on an inconspicuous 

 filiform mycelium, and then exhibit the characters of compound sporophores described 

 in sections XII and XIII. In other species they are produced and borne 

 on larger compound sporophores, each called a stroma, which take the form 

 in the different species of flat expansions, crusts, foliaceous or erect and branched 

 shrublike bodies. The general structure and conditions of growth of these forma- 

 tions, which are often of considerable size, have also been described above in 

 section XII. Well-known examples of them among the Pyrenomycetes are the 

 cushion-like or membranous expanded stromata of the ' Sphaeriae compositae/ i. e. 

 of the genera Hypoxylon, Diatrype, Ustulina, Epichloe, and many others, and the 

 erect sporophores of the Xylarieae, Claviceps, Cordyceps, Thamnomyces with its 

 many bifurcations, and others. Of the Discomycetes which belong to this group 

 the most important are the Lichen-fungi with their disk-shaped and alveolate sporo- 

 carps; next, Rhytisma and its allies with 

 flat disk-shaped stromata, and perhaps too 

 the remarkable South American Cyttarieae 

 spherical or club-shaped or gelatinous 

 bodies more than an inch in diameter 

 with the broad upper half covered with 

 deeply alveolate hymenia, regarding which 

 it is doubtful whether each is in itself a 

 sporocarp or a portion of the sporocarp 

 formed by the whole club-shaped stalk. 



Two chief constituents may be dis- 

 tinguished in almost all the better-known 

 sporocarps of the Ascomycetes (Fig. 85) ; 

 one (c, s, a) is the ascus-apparatus and 

 consists of asci together with the hyphae 

 or cells from which they are immediately 

 derived, the ascogenous hyphae or ascogenous 

 cells', the other is the envelope- apparatus 

 which is formed of all the other parts of the 

 sporocarp. The two parts are necessarily 



in the closest relation to one another from the purely morphological and also from 

 the physiological point of view, since the envelope-apparatus bears, protects, and 

 feeds the asci. The elements of the two parts may be most intimately united 

 and interwoven with one another in the mature sporocarp and in fact may be 

 difficult to separate or distinguish. Nevertheless the origin and growth of the 

 two parts are usually distinct from their first inception or at least in a very early 

 stage of the sporocarp, so that only similar parts, asci, and not elements of the 

 envelope, spring from an ascogenous hypha or ascogenous cell, and no asci from 

 the elements of the envelope. Exceptions to this rule are according to ac- 

 curate observations at least very rare. Former statements to the effect that asci 

 and elements of the envelope, especially paraphyses, spring directly from the same 

 .hyphae are in most cases certainly incorrect; even some recent statements, like 

 those regarding Pleospora and Ascodesmis, which will be noticed again in a 



FIG. 85. Ascobolus fur/uraceiis. Young sporocarp in 

 median longitudinal section; m mycelium, h hymenium. c 

 archicarp with the ascogenous hyphae s in the subhymenial 

 layer and the asci a shaded, / antheridial branch, p r tissue 

 of the envelope giving rise to the paraphyses. Diagram- 

 matic representation from Sachs after Janczewski. 



