344 COMPARATIVE MORPHOLOGY OF FUNGI 



In Lachnea scutellata, which forms shining red fructifications on dead 

 wood, generally no antheridium is formed and the ascogonia develop at 

 once with autogamous pairing of their nuclei (Brown, 1911). 



While in both these cases have been observed types of sexual activity 

 such as can be produced experimentally in Pyronema confluens, three 

 other Pezizaceae, Lachnea abundans, Humaria granulata and H. rutilans, 

 have relationships which extend beyond Pyronema confluens. 



Lachnea abundans connects directly to the parthenogamous Ascobola- 

 ceae (Ascobolus citrinus type). Its archicarp consists of a long, eight- to 

 nine-celled trichogyne, transitorily projecting beyond the hyphal tangle, a 

 three- to four-celled, helical ascogonium and a multicellular stipe. 

 Antheridia have not been observed (Fraser, 1913). In the septa of the 

 trichogyne, nevertheless, transitory pores are formed, possibly as ata- 

 vism; since there are no foreign nuclei to pass through, however, the pores 

 are again closed by callus plugs. Subsequently the septa in the asco- 

 gonium between three to four cells dissolve, nuclear pairing begins and 

 the ascogonium develops, according to the known scheme, to ascogenous 

 hyphae. 



In the second group, Humaria granulata (Blackman and Fraser, 1906; 

 Fraser and Brooks, 1909) and H. anceps var. aurantiaca (Delitsch 1926), 

 the lack of antheridium has progressed so far morphologically that the 

 ascogonium no longer forms a trichogyne. In contrast to Lachnea abun- 

 dans, the ascogonium is unicellular, as in Pyronema confluens and the two 

 first species of Lachnea. It has no trichogyne and hence appears exter- 

 nally like the oogonium of the Oomycetes (Fig. 229, A). Apparently 

 without external cause, the nuclei pair and migrate into the ascogenous 

 hyphae (Fig. 229, C). Here also we have autogamy; because of lack of 

 antheridium, however, there is no trichogyne. 



In Humaria rutilans even the ascogonia, which because of autogamy 

 would be only a detour, are no longer formed and the sexual act takes 

 place between any two vegetative cells in the hypothecium (Fraser, 

 1907, 1908). Autogamy in the interior of special branches of vegetative 

 hyphae differentiated as sexual organs has been replaced by ordinary 

 pseudogamy between the hyphae themselves. With these forms, the 

 sexual processes of the Ascomycetes have reached a stage of degeneration 

 which we shall observe later in various modifications under the 

 Basidiomycetes. 



Cytological investigations of a larger number of Pezizaceae will 

 broaden and deepen the problems indicated here. Thus Otidea aurantia 

 (Fraser and Welsford, 1908), Humaria theleboloid.es (Peziza theleboloides) , 

 Humaria Roumegueri and H. carbonigena (Gwynne-Vaughan, 1922) seem 

 to possess a well-developed uni- or multicellular ascogonial region, while 

 Pustularia vesiculosa (Peziza vesiculosa) (Fraserand Welsford, 1908) Aleuria 

 P. tectorial (tectoria) (Gwynne-Vaughan, 1922) and Plicaria Adae (Peziza 



