32 A MANUAL OF THE PENICILLIA 



forms. In the actual study of large numbers of cultures, however, every 

 gradation between these extremes is found and it often becomes a matter 

 of the judgment of the observer as to the group to which the strain under 

 observation should be assigned. For descriptive purposes, colonies which 

 show a definite and fairly deep aerial felt before the beginning of conidium 

 formation are regarded as lanose or floccose; colonies in which conidial 

 areas follow closely the growth of the mycelium at the colony margin, and 

 do not develop an aerial felt, are regarded as velvety. Modified terms, 

 such as "deeply velvety," have to be introduced occasionally. 



Funiculose (fig. 4A): Some species are characterized by aerial ropes, 

 bundles, or funicles consisting of several to many hyphae. Such bundles 

 may be ascending (fig. 4A) but are rarely, if ever, upright. In the so-called 

 funiculose species, part or all of the fertile hyphae arise as branches from 

 these ropy networks, although simple conidiophores are also found. The 

 funiculose type of colony may be found in each of the major sections of the 

 genus Penicilliwn, and also in the "related" genera Scopidariopsis and 

 Paecilomyces. 



Funiculose masses of aerial hyphae are readily determinable with the 

 lower magnifications of the compound microscope and afford a useful 

 character in the grouping of species. The character is seized upon simpl>' 

 as a useful diagnostic tool rather than an indication of natural relationship 

 since no genetic significance seems to be attributable to its development. 

 Caution should be exercised in interpreting ropiness as a final diagnostic 

 characteristic, because strains from non-funiculose series often tend to 

 develop ropes of aerial hyphae when they become "wet" or otherwise 

 atypical in appearance. If the character is applied, however, to cultures 

 freshly isolated from nature, or to those long maintained in the laboratory 

 without apparent change, it can be extremely useful. 



Fasciculate or Coremiform (fig. 4B): A whole series of forms show the 

 marginal areas of rapidly growing colonies to be rough or granular, or 

 "mealy," to use Westling's designation. Microscopic examination in such 

 cases shows that the rough or mealy appearance is due to the aggregation 

 or fasciculation of conidiophores. In some species, fascicles may be at 

 first clearly noticeable in marginal colony areas, only to become largely 

 obscured later by the crowded development of simple conidiophores in the 

 intervening spaces. In a few cases, such as Penicillium italicum Wehmer, 

 the coremiform structures characteristically appear late in colony develop- 

 ment. In other species, such as P. granulatum Bainier (fig. 4B), the vast 

 majority of the conidiophores are from the first aggregated into well- 

 defined fascicles. Occasionally, in species such as P. claviforme Bainier, 

 conidiophores develop almost exclusively in compact columns, or "stalks", 

 which produce single integrated conidium-bearing heads (fig. HOB). 



