cultivation and preservation of penicillia 87 



Preservation of Species Types 



DRIED specimens 



In general botanical taxonomy the description of a species should apply 

 to a particular specimen marked as type and deposited in some accessible 

 collection for reference. In the case of Penicillium, earlier workers have 

 commonly deposited such type specimens in herbaria. Oftentimes these 

 consisted of natural specimens such as rotted fruit. In some cases they 

 represented colonies grown by conventional means but transferred and 

 dried on sheets of cardboard; in other cases they consisted of portions of 

 colonies mounted inside paper boxes designed to protect aerial parts; in 

 still other cases cultures dried in original tubes or petri dishes have been 

 preserved. Specimens of the latter type generally offer the most satis- 

 factory material, since they retain the original colony characters in least 

 altered form. The preservation of such dried specimens, while highly 

 desirable, gives only limited satisfaction. AMien cultures of Penicillium 

 become thoroughly dry the mycelium and fructifications of most species 

 are exceedingly fragile and usually break up completely when attempts 

 are made to prepare microscopic mounts. In many cases the form and 

 dimensions of conidia represent the only points which can be established 

 with any degree of certainty and even here errors may occur as a result of 

 drying to give a shriveled appearance. 



LIVING collections 



The preservation of living type material, if handled with scrupulous 

 care, affords the best solution in the case of most Penicillia. For this 

 reason collections of Penicillium and other saprophytic molds have gradu- 

 ally been built up. If such collections, however, are not expertly handled 

 the strains contained in them may not only fail to represent the original 

 types but may, in fact, be very misleading in giving the worker a false 

 sense of security. The existence of certain species which tend to degener- 

 ate under continuous laboratory cultivation represents the most serious 

 objection to this method of preserving type material. 



Bainier, in Paris, maintained a fairly large collection until his death. 

 This was subsequently taken over by other workers and what remained 

 of it in 1922 was sent to Thom by daFonseca. Westling's cultures had 

 been previously received in 1911. Biourge inherited the collection left 

 by Dierclvx and augmented it greatly by the isolation of additional strains 

 in Europe. His collection was sent to Thom prior to the publication of the 

 latter's IMonograph in 1930. Some additional cultures from Biourge's 

 collection were brought to this country in 1936 by Professor Paul Simonart 

 who succeeded Biourge at the University of Louvain. In 1940, the collec- 



