MYCOLOGIA 



Vol. XII July, 1920 No. 4 



OBSERVATIONS ON THE GENJ^g^^ 

 ACROSPERMUM 1 



(AUG 12 1920 



Lincoln W. Riddle V 

 (With Plate ii, Containing 13 Figures) ^^ £j,on»l ^ ^S--^ 



Acrospermum is the name given to a small group of closely 

 related fungi growing on living or dead herbaceous plants or 

 plant-parts. The genus was established in 1790 by Tode in his 

 Fungi Mecklenburgenses (part i, page 8), with Acrospermum 

 compressum as the type-species. The plants all have erect fructi- 

 fications, more or less clavate or spatulate in form. The asci are 

 elongated; contain eight filiform, colorless spores; and are sur- 

 rounded by capillary paraphyses. The texture is horny when 

 dry, fleshy-cartilaginous when moist. There are two peculiarities 1 

 which have made the systematic position of the" genus uncertain: 

 the fructification is ordinarily compressed (compare Figs. 1 and 

 2), and the ostiole is elliptical rather than circular (Fig. 5). 

 Ellis and Everhart (North American Pyrenomycetes p. 67, 1892) 

 placed Acrospermum in the Hypocreales, to which it is obviously 

 allied in texture and in the coloration of most of the species. 

 Rehm, however, transferred the genus to the Hysteriales, because 

 of the two peculiarities mentioned above, and this disposition has 

 been accepted, by Lindau, in Engler and Prantl, where he estab- 

 lished a family, Acrospermaceae, in the Hysteriales. 



Such an arrangement seems scarcely to express natural rela- 

 tionships since all of the Hysteriales are characteristically car- 



1 Contribution from the Cryptogamic Laboratories of Harvard University, 

 No. 88. 



[Mycologia for May (12: 115-174) was issued June 5, 1920.] 



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