MONOVERTICILLATA 129 



bb. Ascospores lenticular, about 3.5 to 4.0m in long axis with 

 walls strongly echinulate and furrow generally pro- 

 nounced; penicilli reduced or fragmentary 



P. ehrlichii Klebahn 146 

 cc. Ascospores lenticular, about 4.0/* in diameter, not furrowed 

 or showing only an equatorial line, with walls smooth; 

 penicilli verj' reduced, often appearing as single sterig- 



mata P. levitum Raper and Fennell 148 



b. Penicilli typically biverticillate but with monoverticillate struc- 

 tures produced, and with perithecia at first sclerotioid and ripen- 

 ing late Carpenteles series 260 



(in the Divaricata, pp. 260-273) 

 2. Perithecia soft, loose-textured, without a definite or firm outer wall; 

 penicilli commonly fragmentary, often appearing monoverticillate. 



a. Ascospores large, 7.0 to S.oju in long axis, broadl}' elliptical, with 



5 to 8 prominent longitudinal flanges or ridges showing in side 

 view, without definite equatorial furrow 



P. striatum Raper and Fennell 

 (in P. luteum series) 



b. Ascospores small, 2.8 to 3.2/* in long axis, with a single equatorial 



ridge or two ridges closely appressed P. stipitatum Thom 



(in P. luteum series) 

 B. Colonies producing sclerotia, often suggestive of young perithecia but 

 never developing an ascogenous stage. 



1. Penicilli strictly monoverticillate. 



a. Sclerotia produced upon all substrata, hard, brittle, crushing with 



difficulty, composed of thick-walled sclerenchj^ma-like cells 



P. thomii series 154 lX 

 1'. Sclerotia borne in clusters of varying size, surrounded by con- 

 spicuous envelopes of bright orange-red mycelium, character- 

 izing the colony on some substrata 



P. sclerotiorum van Beyma 160 i/ 

 2'. Sclerotia in pink shades, not in clusters and not embedded in 



masses of orange-red hj'phae P. thomii IMaire 156 '^ 



3'. Sclerotia in orange-brown shades, not in clusters, often sur- 

 rounded bj' a loose network of yellow to orange or light brown 

 mycelium P. lapidosum Raper and Fennell 163 



b. Sclerotia produced upon some substrata, not on others including 



Czapek, comparatively soft, composed of pseudo-parenchyma- 



tous cells with walls thickened P. turbatum sub-series 166 



1'. Colonies on Czapek agar not developing dull, dark purple colors 



in reverse, somewhat restricted P. turbatum Westling 166 



2'. Colonies on Czapek agar developing dull, dark purple colors in 



reverse, very restricted P. pusillum Smith 167 



2. Penicilli typically biverticillate-asymmetric P. raislrickii series 



(in the Divaricata, pp. 273-283) 

 II. Colonies not producing perithecia or sclerotia. 



A. Conidiophores generally unbranched and bearing single, strict!}^ mono- 

 verticillate penicilli. 

 1. Colonies velvety or nearly so, with conidiophores arising mostly from 

 the substratum. 



