lgS 



DIVISION II. — COURSE OF DEVELOPMENT OF FUNGI. 



transverse diameter of the mycelial hypha 10 times or more (&). Then they cease to 

 lengthen, are delimited from their parent-hyphae and conjugate at their summits, the 

 cell-walls disappearing at the point of contact and the two protoplasmic bodies 

 coalescing into one (c). The place of conjugation then swills into a spherical vesicle, 

 which is delimited when tin- protoplasm of the pair of cells has passed into it, and 

 having thus become an ascus forms 8 spores capable of germination (//-_/"). The 

 spores are formed, as far as can be gathered from Eidam's somewhat superficial 

 description, in the manner described in section XIX. No further complications have 

 been observed in the formation of these sporocarps. 



2. Distinct archicarps are formed as branches on the mycelium or on vegetating 

 hyphae in the thallus singly, or rarely in groups, as in Pyronema and Physma. It 

 depends on the species whether the archicarp is a single cell or, as is more com- 

 monly the case, a cell-row, and whether it is spirally coiled or of some other shape. 

 The whole ascus-apparatus of the sporocarp is derived exclusively from the archi- 

 carp. In Podosphaera a single ascus borne on a short stalk-cell is formed by 



transverse division of the uni- 

 cellular archicarp; in other species 

 ascogenous hyphae sprout as 

 branches from the archicarp, or 

 the cells of the archicarp divide 

 into ascogenous daughter-cells, 

 that is, into daughter-cells which 

 sprout out into asci. The archi- 

 carp takes no part in the forma- 

 tion of the envelope-apparatus, 

 that is, of the wall, receptaculum, 

 excipulum, paraphyses, &c. This 

 has its origin in the hyphal 



1 92. Ertmascus albus. a inception of the sporocarp. b—f 

 further development in the succession of the letters. In / 

 matured and the spores formed in it. After Eidam. Magn. 900 times. 



branches which arise in the neigh- 



bourhood of the archicarp, usually 

 at its base, and grow round the ascus-apparatus in a way which is determined by 

 the species. From this specific ascogenous function the archicarp may in this case 

 be termed an ascogonium. It has also been called a carpogonium. Of cleistocarpous 

 and pyrenocarpous forms the Erysipheae, Eurotium, Penicilliiirn. Sordaria 

 (Hypocopra), and Melanospora parasitica belong to this section ; of gymno- 

 carpous and discocarpous forms Gymonoascus, Pyronema, Ascobolus, and the 

 Collemaceae which were examined by Staid (C'ollema, Synechoblastus, Leptogium, 

 Physma, &c). 



In a number of the species of this division an antheridial /'ranch makes its 

 appearance in characteristic form in connection with the archicarp before the com- 

 mencement of the formation of asci. This is the case especially with Pyronema, 

 the Erysipheae, Hypocopra, Gymnoascus, and Eurotium. In Pyronema, before further 



lopment begins, conjugation, the union of the two protoplasmic bodies into one, 

 takes place between antheridial branch and archicarp, by means of a special appa- 

 ratus belonging to the archicarp, the trichogym, and the same thing happens in 

 less striking form in Eurotium. In the Collemaceae the antheridial branches are 



