GROUP I. THALLOPHYTA : FUNGI. 



291 



rise to several filaments termed stromata, about an inch long, each 

 composed of a strand of hyphse, which bear a swollen knob at their 

 apices (Fig. 176). All over the surface of the 'knob are a number 

 of depressions, in each of which there is an ascocarp (perithecium) 

 containing a number of asci, and in each ascus there are eight 

 filiform ascospores. The ascospores are carried by the wind to the 

 Rye-fbwers and there give rise to the Sphacelia-fonn. 



In some cases only conidia-bearing forms are known (e.g. Asper- 

 gillus clavatus, Botrytis Bassii, species of Isaria, Cladosporium 

 Iferbarum, etc.). 



The Reproductive Organs are asexual and sexual. 



The asexual organs are conidiophores, either simple or compound 

 (see Figs. 170, 175), branched or un- 

 branched ; the conidia are formed 

 by abstriction from short tubular 

 outgrowths of the unbranched, or 

 of the terminal cells of branches 

 of the branched, conidiophore, 

 termed sterigmata. In many cases 

 the conidiophores are collected into 

 special receptacles termed pycni- 

 dia. 



The sexual organs are modified 

 hyphse. They may be unseptate 

 (e.g. Eremascus, Eurotium Asper- 

 gillus, Pyronema), or septate (e.g. 

 Ascobolus, Laboulbeniacese) ; they 

 may be quite similar (e.g. Eremas- 

 cus) or more or less differentiated ; 

 they may come into close contact 

 (e.g. Eremascus, Eurotium, Pyronema). 



When, as in Eremascus, the sexual organs are undifferentiated, 

 no special names are given to them ; but when they are differen- 

 tiated the female organ is termed an archicarp, and the male 

 organ a pollinodium, when its contents do not undergo differen- 

 tiation into cells, or an antheridium when (as in the Laboul- 

 beniaceee) male cells are formed in it. 



In some forms (e.g. Laboulbeniacese, Pyronema) the archicarp 

 consists of two parts ; a receptive portion, filamentous in form, the 

 trichogyne; a fertile portion, the ascogonium (compare Rhodo- 

 phycese, p. -272). In the simpler forms, the trichogyne is absent 



FIG. 170. Conidiophore of Penieil- 

 lium j/lnucnm : s a row of conidia on a 

 sterigma ; m hypha of the mycelium 

 (x!50.) 



