HELIOTROPISM OF ASCI IN DISCOMYCETES 281 



W. H. Brown ^ has given us an interesting account of the develop- 

 ment of the fruit-body. He discovered that, if fruit- bodies which 

 are developing on a log of wood are picked off, a new crop of fruit- 

 bodies soon makes its appearance. Taking advantage of this fact, 

 he obtained a series of very young fruit-bodies which he was able 

 to investigate with the help of the microtome. He found that each 

 fruit-body develops (c/. Fig. 134) from an archicarp,^ the penultimate 

 cell of which swells up greatly and becomes the ascogonium or 

 ascogenous cell. This ascogenous cell, which is multinucleate, sends 

 out ascogenous hyphae which grow upwards, branch and rebranch 

 and, finally, after hook-formation and conjugate nuclear divisions, 

 produce the asci. Each ascus contains two nuclei which fuse 

 together. The fusion nucleus then undergoes the usual sub- 

 divisions, so that eight nuclei result. The eight nuclei eventually 

 become enclosed in the eight spores. No antheridium could be 

 observed, so that there is no evidence that the ascogenous cell 

 receives any male nuclei. The vegetative hyphae at the base of the 

 archicarp grow in length, branch freely, and produce the paraphyses, 

 the trama, and the outer covering of the fruit-body including the 

 setae. Brown's diagram illustrating the mode of development of 

 the fruit-body is reproduced in Fig. 134. 



The red colouring matter of Ciliaria scutellata, like that of 

 Pilobolus, the Uredineae, Polystigma rubrum, Nectria cinnabarina, 

 Peziza aurantia, etc., is held in tiny oil drops and is therefore a 

 lipochrome.^ The lipochromes are regarded as carotins.^ They are 

 insoluble in water, but soluble in alcohol, ether, chloroform, etc. 

 When dry, with concentrated sulphuric acid, they give the typical 



^ W. H. Brown, Joe. cit., pp. 275-305, with 51 Figs, in the text and one Plate. 



^ M. Woronin was the first to see and illustrate the archicarp of Ciliaria scutellata. 

 He said that it consisted of a chain of 2-5 cells which soon became surrounded by 

 vegetative hyphae which obscured its further development. Vide his " Die 

 Entwicklungsgeschichte des Ascoholus pulcherrimus und einiger Pezizen " in 

 de Bary and Woronin 's Beitnige zur Morphologie und Physiologie der Pilze, No. II, 

 1866, pp. 5-6, Plate II, Figs. 1-3. 



^ VV. Zopf, '" tjber das mikrochemische Verhalten von Fettfarbstoffen usw.," 

 Zeitschr.f. wiss. Mikroscopie, Bd. VI, 1889, p. 172; also Die Pilze, Breslau, 1890, 

 pp. 146-147. 



* Cf. J. Zellner, ('hfrnip der Hohfrni Pilze. Leipzig, 1907, pp. 12, 139-142 ; and 

 Hans Molisch, Mikrochenric dvr Pflanzen, 1923, p. 221. 



