In _Anaptychia ciliaris_ he was able to pick out extremely early stages by staining with a solution of chlor-zinc-iodine. Mäule[564] applied the same test to _Physcia pulverulenta_, but found that to be successful the reaction required some time. Certain cells of the hyphae—mostly terminal cells—in the lower area of the gonidial zone and even occasionally in the pith (according to Lindau) coloured a deep brown, while the ordinary thalline hyphae were tinted yellow. He assumed that these were initial ascogonial cells on account of the richer plasma contents, and also because of the somewhat larger size of the cells. In the same region of the thallus young carpogonia were observed as outgrowths from vegetative hyphae, though the trichogynes had not yet reached the surface. [Illustration: Fig. 93. _Physcia pulverulenta_ Nyl. Vertical section of thallus and carpogonium before fertilization. _a_, outer cortex; _b_, inner cortex; _c_, gonidial layer; _d_, medulla. × ca. 540 (after Darbishire).] [Illustration: Fig. 94. _Physcia_ (_Anaptychia_) _ciliaris_ DC. Vertical section of developing ascogonium. _a_, paraphyses; _b_, ascogonial hyphae; _c_, ascogonial cells. × 800 (after Baur).] At a more advanced stage the carpogonia were seen to be embedded in the gonidial zone and occurred in groups. The cells of the ascogonium, easily recognized by the darker stain, were short and stout, measuring about 6-8µ in length and 4·4µ in width. They were arranged in somewhat indistinct spirals; but the crowding of the groups resulted in a confused intermingling of the various generative filaments. The trichogynes composed of longer narrower cells rose above the hyphae of the cortex; they also stained a deep brown and the projecting cell was always thin-walled. Lindau frequently observed spermatia very firmly attached to the trichogyne cell but without any plasma connection between the two. The changes in the trichogyne described by Stahl and Baur in Collemaceae were not seen in _Anaptychia_; the peculiar swelling of the septa seems to be a phenomenon confined to gelatinous lichens. During the trichogyne stage in this lichen the vegetative hyphae from the medulla grow up and surround the young carpogonia, and, at the same time, very slender hyphae begin to branch upwards to form the paraphyses. Darbishire’s[565] examination of _Physcia pulverulenta_ demonstrated the presence of the coiled ascogonium and the trichogyne in that species (Fig. 93).