(1) The carpogonia arise in a complex of hyphae situated on the under side of, or immediately below the gonidial zone. Usually they vary in number from five to twenty for each apothecium, though as many as seventy-two have been computed for _Icmadophila ericetorum_[570], and Wainio[571] describes them as so numerous in _Coccocarpia pellita_ var., that their trichogynes covered some of the young apothecia with a hairy pile perceptible with a hand lens, though at the same time other apothecia on the same specimens were absolutely smooth. (2) The trichogynes, when present, travel up through the gonidial and cortical regions of the thallus; Darbishire[572] observes that in _Physcia pulverulenta_, they may diverge to the side to secure an easier course between the groups of algae. They emerge above the surface to a distance of about 15µ or less; after an interval they collapse and disappear. Their cells, which are longer and narrower than those of the ascogonium, are uninucleate and vary in number according to species or to individual lichens. Baur[573] thought that possibly several trichogynes in succession might arise from one ascogonium. (3) How many carpogonia share in the development of the apothecium is still a debated question. In _Collema_ only one is functional. Baur[574] was unable to decide if one or more were fertilized in _Parmelia acetabulum_, and in _Usnea_ Nienburg[575] found that, out of several, one alone survived (Fig. 95). But in _Anaptychia ciliaris_ and in _Lecanora subfusca_ Baur[574] considers it proved that several share in the formation of the apothecium. In this connection it is interesting to note that, according to Harper[576] and others, several ascogonia enter into one _Pyronema_ fruit. [Illustration: Fig. 95. _Usnea barbata_ Web. Carpogonium with trichogyne × 1100 (after Nienburg).] (4) The ascogonial cells, before and after fertilization, are distinguished from the surrounding hyphae by a reaction to various stains, which is different from that of the vegetative hyphae, and also by the shortness and width of their cells. The whole of the apothecial primordium is generally recognizable by the clear shining appearance of the cells. (5) The ascogonia do not always form a distinct spiral; frequently they lie in irregular groups. Each cell is uninucleate and may ultimately produce ascogenous hyphae, though in _Anaptychia_ Baur[574] noted that some of the cells failed to develop.