Thom and Turesson: Penicillium avellaneum 285 
200 fx. long, composed of loosely parallel or tangled chains of 
conidia ; fertile branches either a terminal crowded verticil of 
metulae 8-io by 3 ju, bearing verticils of few sterigmata 8-9 X 2/^, 
or with branches more or less irregularly disposed over the ter- 
minal 10-15 /I. of the conidiophore ; conidia ellipsoid to almost 
globose, 2-2.5 X 3“3-5 /^, smooth, swelling in germination to 5 ju 
in diameter and producing a single tube. 
Fig. I. a, b, c. Young conidial apparatus showing variation in branching; 
d. an occasional case of superposed verticils ; e, a typical single verticillate 
fruit ; f, diagrammatic representation of whole conidial fructification ; g, 
conidia ; h, conidia swollen and each producing one germ tube ; i, ascospores 
with thick walls apparently fitted ; magnification a, b, c, d, e, g, h, i, X 900 ; 
f, X 260. 
Perithecia ellipsoid to globose 300-600 ix in diameter, originat- 
ing as an ascigerous mass surrounded by numerous swollen, very 
thick-walled cells, with the slow development of a peridium com- 
posed of thick-walled cells, 8-12 /a in diameter in one or some- 
times two layers; asci 9-10 X 12-15 /a, 6-8-spored ; ascospores 
ellipsoid, 4-5 X 6.5-8. 5 /a, with walls thick, pitted or with the ap- 
pearance of round, transparent spots. 
