62 



CULTURAL STUDIES OF SPECIES OF PENICILLIUM. 



centibus ; in agaro latioribus ; parte aeria ex conidiophoris et fructibus eonidicis creber- 

 riniis eomposita, interdum eaespitibus paucis hyphorum adscendentum in medio; 

 reverso incolorato; conidiophoris (sine ramis) non longioribus 150/<, singulatim orienti- 

 bus, aut paueis ex hyphis adscendentibus ramosis; fructibus eonidicis 3-5 ramorum 

 16-30X3,u, apice 5fi incrassatorum, in verticillo, basidia in verticillis compactis 

 gerentum; utroque verticillo catenis conidiorum in columno compacto 50-150/t 

 longos adhaerentibus; basidiis 6-7X2-3/*; conidiis globosis, 2.4-3/x raro 3.5/t diam., 

 aeruginoso-glaucis, granulatis intus, in catenis manentibus submersis. 



Coloniis, saccharo commixto, substrata citrina in colore efficientibus (ubi nomen). 



Habitat, in caseo, pane, etc., commune (?). 



Colonies grown upon gelatin and potato or bean agar blue-green when young, 

 becoming dark brown when old, with colored fruit borne almost to the very margin 



mm 



mm 



FlG. 22. — Penicillium citrinum: a, b, e, /, </, branching of conidial fructification, showing number of 

 branches in each verticil and enlargement of ends of branches (a X 900, others X 1.600); c, d, n, eonidiif- 

 erous cells and the formation of conidia (X 1,600); h, j, k, I, m, sketches of conidial fructifications 

 (X 140); o, s, t, germination of spores (X 900). 



of the colony, so that the white border of submerged mycelium and uncolored fruit 

 is very narrow; restricted in growth to a few millimeters in diameter upon gelatin, 

 but becoming much larger upon agar; aerial part of colony consisting of densely 

 standing conidiophores and conidia except in the center, where there arise a few tufts 

 of trailing aerial hyphae. Reverse of colony itself colorless or only yellowish. Conidio- 

 phores arising separately, rarely longer than 150/*, branching acropetally from sub- 

 merged hyphae radiating from the center of the colony, or branched from the hyphae 

 of the central aerial tuft. Conidial fructification a verticil 2 to 5 branches 16-30 by 3/z 

 enlarged at apex to 5/*, each producing a compact verticil of conidiiferous cells bearing 

 chains of conidia massed together into columns 50-150/* in length (usually 80-100/i). 



