224 BOTANICAL GAZETTE [September 



The questions of morphology and parasitism of this fungus are of 

 especial interest. The morphological characters to be emphasized 

 are the internal intracellular mycelium, the external fungous layer 

 which becomes the cover of a dimidiate pycnidium, the dome- 

 shaped, flat-bottomed perithecium with a wall several cells thick 

 and without ostiole. The habit of the mycelium of completely 

 fining certain cells or irregular groups of cells while intervening and 

 adjacent cells are entirely free of mycelium is striking. The whole 

 picture gives a group of characters difhcult to place satisfactoril}'. 

 The mycelial characters are Microthyriaceous, the absence of 

 ostiole Perisporiaceous, and it might be possible to regard the peri- 

 thecial cavity as being in a stroma and thus incline toward the 

 Dothidiaceae. It is also possible, when the top is fallen out of the 

 perithecium, to regard it as Phacidiaceous, and it is here that we 

 would place it, although the mode of formation and of opening of the 

 perithecium are not fully characteristic of that family. The genus 

 Rhagadolobium, described on a tropical fern (Henning and Lindau 

 in Engler's Jahrb. 23:288. 1896), presents certain similarities in the 

 structure of the stroma, although it differs essentially in many 

 ways, particularly in having the mycelium intracellular rather than 

 intercellular, and in having i-celled spores. In the Dothidiales 

 the fungus resembles Rhipidocarpon Th. and Syd. in structure of 

 the perithecium as seen in section, but the perithecium is not radial. 

 In fact, it presents essential differences from all of the families of the 

 Dothidiales as set up by Theissen and Sydow. The fungus clearly 

 shows differences from established genera sufficient to render its 

 admission to any of them impossible. We therefore propose for it 



the new genus : 



Griggsia, gen. no v. 



Perithecia solitary, dimidiate, without ostiole, opening by irregu- 

 lar cleavage of the top, arising from a thin superficial and epidermal 

 stroma, vegetative mycelium internal. Perithecial wall several 

 cells thick. Asci basal, 8-spored. Spores oval, hyaline, i-celled. 

 Paraphyses hyaline, long, filamentous. Conidia in dimidiate 

 pycnidia. Type species Griggsia cyathea. , Named in honor of 

 RoBT. F. Griggs. 



Griggsia cyathea, sp. nov. — Perithecium dome-shaped. 200- 

 300 M in diameter, 150-160 ^ high; wall about 24 jx thick on sides 



