342 MORPHOLOGY OF THE ASPERGILIACE^. 



substance, it forms the pungent compound, diethylarsine (see 

 p. 407). The morphological and biological conditions have 

 recently been more closely described by Stoll (I.), though not 

 exhaustively so. The growths are brownish yellow to brown 

 in colour, according to the age and substratum. The coni- 

 diophores (Fig. 182) are delicate and small, irregularly branched, 



FIG. 182. Peuicillium brcvicaule. 



Formation of conidia on sped il conidiophores (i and 2), as also directly on the my- 

 celium (3), the former on wort gelatin, the latter on an agar-agar culture. The 

 conidiophorc i carries only young, elongated conidia in coiirse of development, 

 those on 2 being ripe and partly shed, together with three younger ones not yet 

 septated (see also fig. 177, 2). Approx. uiagn. of i and 2, 500 aud 800 respectively; 

 of 3, 400. (Original.) 



and usually with but few twigs and steiigmata, the latter 

 being rather long (about 16 by 3.5 ^) but not very charac- 

 teristic. According to Stoll, there are two forms of the smooth, 

 yellowish conidia, one being spherical (about 6.5 /i in diameter), 

 the other pear-shaped (10 by 6 jj). Saccardo mentions spherical 



