Baur[566] has also given the results of an examination of _Anaptychia_. He frequently observed copulation between the spermatium and the tip of the trichogyne, but not any passage of nucleus or contents. After copulation the ascogonial cells increased in size and became irregular in form, and open communication was established between them (Fig. 94). There was no increase in their number by intercalary division as in _Collema_. After producing ascogenous hyphae the cells were seen to have lost their contents and then to have gradually disappeared. The fertile hyphae, which now took a blue colouration with chlor-zinc-iodine, gradually spread out and formed a wide-stretching hymenium. Several carpogonia took part in the formation of one apothecium. The tissue below the ascogonium meanwhile developed vigorously, forming a weft of encircling hyphae, while the upper branches grew vertically towards the cortex. Gonidia in contact with the developing fruit also increased, and, with the hyphae, formed the exciple or thalline margin. The growth upward of the paraphyses raises the overlying cortex which in _Anaptychia_ is “fibrous”; it gradually dies off and allows the exposure of the disc, though small shreds of dead tissue are frequently left. In species such as those of _Xanthoria_ where the cortex is of vertical cell-rows, the apothecial hyphae simply push their way between the cell-rows and so through to the open. Baur found the development of the apothecium somewhat similar in the crustaceous corticolous lichen, _Lecanora subfusca_. After a long period of sterile growth, spermogonia appeared in great abundance, and, a little later, carpogonia in groups of five to ten; the trichogynes emerged very slightly above the cortex; they were now branched. The ascogonia were frequently a confused clump of cells, though sometimes they showed distinct spirals. The surrounding hyphae had taken a vertical direction towards the cortex at a still earlier stage, and the brown tips were visible on the exterior before the trichogynes were formed. The whole growth was extremely slow. In _Physcia stellaris_ the carpogonia occurred in groups also, though Lindau[567] thinks that, unlike _Anaptychia_ (_Physcia_) _ciliaris_, only one is left to form the fruit. Only one, according to Darbishire[568], entered into the apothecium in the allied species, _Physcia pulverulenta_. In the latter plasma connections were visible from cell to cell of the trichogyne, and, after copulation with the spermatium, the ascogonial cells increased in size—though not in number—and the plasma connections between them became so wide that the ascogonium had the appearance of an almost continuous multinucleate cell or coenogamete[569]. As in gelatinous lichens, each of these cells gave rise to ascogenous hyphae. _c._ GENERAL SUMMARY. The main features of development described above recur in most of the species that have been examined.