HELIOTROPISM OF ASCI IN DISCOMYCETES 273 



eight violet spores and also executes the heliotropic curvature 

 toward the source of light. 



The paraphyses of Ascobolus magnificus are slender and loosely 

 arranged, and they are embedded along with the asci in a gelatinous 

 matrix ; moreover, they are not responsive to heliotropic stimuh. 

 In being anheliotropic they differ from the paraphyses of some 

 Pezizaceae, such as Aleuria vesiculosa. Whereas in Ascobolus 

 magnificus the heliotropic curvature of the asci is accomphshed 

 above the level of the apical ends of the paraphyses, in Aleuria 

 vesiculosa it is accomplished chiefly below that level (c/. Figs. 130 

 and 140, p. 293). 



Ascobolus stercorarius. — Ascobolus stercorarius {^ A. fur- 

 furaceus), an apandrous Discomycete, the archicarp (scolecite) of 

 which was first seen by Tulasne ^ in 1866, has yellowish discoid 

 fruit-bodies, 0- 5-5-0 mm. in diameter, which in Europe and 

 North America commonly appear in pastures on the dung of 

 horses, cows, and other herbivora. 



The apothecium of Ascobolus stercorarius, as found by Janczewski 2 

 in 1871, is at first angiocarpous. The stages in its development 

 have been represented diagrammatically by Corner ^ (Fig. 131) and 

 have thus been described by him. An archicarp arises on the 

 mycelium and one of its cells becomes the ascogonium which 

 collapses about the time when the asci appear. " In the first stage 

 (Fig. 131, a) sterile hyphae arise from the stalk of the archicarp or 

 from adjacent mycelial hyphae and envelop the ascogonium in a 

 loose weft (6). The hyphae branch profusely, especially to the 

 inside, which suggests a sympodium, and the branches apparently 



^ L.-R. and C. Tulasne, " Note sur les phenomenes de copulation que presentent 

 quelques champignons," Ann. de Sci. Nat., ser. V, T. 6, 1866, p. 215. A median- 

 longitudinal section of a young fruit-body of A.furfuraceus, schematically represented 

 by Sachs on the basis of a drawing by Janczewski {Bot. Zeit., 1871, Taf. IV), is 

 reproduced in de Bary's Vergleichende Morphologie und Physiologie der Pilze (1884, 

 pp. 201 and 223). R. A. Harper (Jahrh. /. wiss. Bot., XXIX, 1896) and E. J. 

 Welsford {New Phytologist, VI, 1912) found that A. furfuraceus lacks antheridia 

 and is therefore apandrous. 



2 E. V. G. Janczewski, " Morphologische Untersuchungen iiber Ascobolus 

 furfuraceus," Botanische Zeitung, Jahrg. XXIX, 1871, pp. 271-276, Taf. IV, Fig. 21. 



^ E. J. H. Corner, " Studies in the Morphology of the Discomycetes. II. The 

 Structure and Development of the Ascocarp," Trans. Brit. Myc. Soc, Ve»l. XIV, 

 1929, pp. 277-278. 



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