596 A MANUAL OP THE PENICILLIA 



occur usually in simple verticils of five or six. They are typically acumi- 

 nate to lanceolate, hence characteristic of the Biverticillata-Symmetrica sec- 

 tion of the genus. A single side branch frequently occurs, suggesting a bi- 

 verticillate condition, or two, three, or rarely more shorter branches may 

 form a true verticil of metulae and constitute a definitely biverticillate 

 penicillus. The conidia are unique among the Penicillia. They are rod- 

 Uke in form, 3 to 6/i by 1.0 to 1.5ju, becoming slightly larger at one end with 

 maturity, and in very old cultures approaching an oval contour. The 

 terminal spore of each chain is consistently shorter than the others and 

 nearly oval. They develop in long divergent and tangled thread-like 

 chains which break up readily in old cultures but are quite persistent when 

 young, at which time the individual spore limits are often barely discerni- 

 ble. Perithecia are approximately globose, non-ostiolate, average about 

 137 to 150/x in diameter, and are surrounded by a loose net of branching 

 roughened hyphae usually pale yellowish in color. Asci begin to show 

 mature ascospores within twelve to fifteen days on cornmeal agar at room 

 temperature. Ascospores are spherical, 3.5 to 4.0ai in diameter, very finely 

 verrucose, at first hyahne, but in age may show an orange-yellow tint. 

 Upon germination they swell to about twice their normal size and send out 

 one or two germ tubes [fide Swift). The mycelium is hyahne, branching, 

 septate, 2.5 to 4.0/x, and often roughened with yellowish deposits particu- 

 larly about the perithecia. 



Emmons (1935) reported and figured the perithecial initials of this species 

 as a pair of short coiled hyphae. In our examination of the type, we have 

 observed structures which seem to fit this interpretation. We have not, 

 however, succeeded in estabhshing, with certainty, that perithecia develop 

 from the coiled structures observed in our cultures. 



The species is represented only by the type strain. It was received 

 from Swift prior to the pubhcation of her species, and has been continued 

 in laboratory culture since that time. It is now maintained in our Collec- 

 tion as NRRL 1025. The culture, as examined during the current study, 

 differs from its original aspect only in producing relatively fewer perithecia 

 on Czapek agar and apparently ripening ascospores somewhat more tardily. 



The species is distinguished by the bacillary form of its conidia, from 

 which it takes its name. It is also characterized by the production of 

 globose, echinulate ascospores, a pattern unique to this species and Peni- 

 cillium rotundum, recently described by Raper and Fennell (1948). The 

 production of peniciUi that are usually monoverticillate suggests relation- 

 ship to the ascosporic series of the section Monoverticillata. Such a place- 

 ment, however, is counter-indicated bj^ the presence of lanceolate to acu- 

 minate sterigmata (characteristic of the Biverticillata-Symmetrica) and the 

 formation of perithecia bounded by a network of interwoven hyphae rather 



