THE PSEUDORHIZA OF COPRINUS MACRORHIZUS 363 



surface of the substratum, the pseudorhiza becomes about four 

 inches long (Fig. 186, p. 369). 



The development of a fruit- body primordium will now be 

 described in detail. The pseudorhiza of a fruit-body which has 

 originated a few inches below the surface of the manure and which 

 has shed its spores and withered away aerially sometimes develops 

 a large number of primordia ; and, occasionally, some of these 

 primordia develop into fruit-bodies which produce pseudorhizae of 

 their own, come above groimd, and open out in the usual manner 

 (Fig. 187, p. 371). The primordia arising on old pseudorhizae 

 develop in just the same manner as those produced directly on the 

 surface of a straw and are easier to procure. Old pseudorhizae 

 bearing primordia were therefore used for studying the earUest 

 stages of fruit- body development. 



The material was fixed ^ in Fleming's fluid (weaker solution) 

 for 24 hours, washed for 24 hours in running water, and then placed 

 in 30 per cent, alcohol. It was then brought up gradually to absolute 

 alcohol and, after being passed through xylol in the usual manner, 

 was embedded in paraffin. Sections were cut with the microtome 

 and double-stained in iron-alum-haematoxylin ^ and Bordeaux red.^ 



The earliest stages in the development of the fruit-bodies of 

 Coprinus macrorhizus are very similar to those of Psallio'a campestris 

 described by Atkinson * in 1906. The primordium of the carpophore 

 as a whole in its youngest state is a homogeneous body composed 

 of slender uniform dense hyphae which are woven in a complex 

 manner into an even meshwork, and surrounded by a thin layer of 

 hyphae which are looser and less dense in their arrangement. This 

 outer looser layer can be considered as a universal veil. It is quite 

 distinct in all the youngest stages (Figs. 183 and 184) and grows 

 for some time. Finally, it ceases to grow and, as the pileus expands, 

 splits up and thus gives rise to the hairy scales which are such a 



* <'f. Chamberlain, Methods in Plant Histology, Chicaffo, 190."). p. 248. 



^ This was the .same as Haidenhain's solution {vide Chamberlain, loc. cit., p. 250) 

 except for the fact that 1 ■ 5 per cent, aqueous solution of iron alum was used instead 

 of ferrous ammonium sulphate. 



^ A 1 per cent, aqueous solution for 3 minutes. 



* ('•. F. Atkinson, " The Development of Agaricus campestris," Botanical Gazette, 

 Vol. XLII, 190(j, pp. 241-264. 



