190 



The plant affixes itself to the substances on which it grows 

 by spongy tufts of confusedly packed, strong fibres, occasional- 

 ly jointed by transverse partitions, whose extremities are blunt- 

 ed or obtuse, and the color of which appeared to be of a dark 

 limber, although the entire mass seems of a greyish hue. 

 These tufts issue from the veins and are of an oblong or ellipti- 

 cal shape and outline and not very numerous. 



The apothecia are borne upon the edges or margin of the 

 thallus and occur frequently within a notch or sinus : they are 

 subpedicillate, have a broad thalline exciple, lacerated on its 

 margin and which disappears with age, leaving the apothecia 

 somewhat convex. The disk is at first of a bright chesnut 

 color but becomes blackish. The thickened epidermal cells are 

 very apparent in a longitudinal section of the apothecium, and 

 upon these cells a very loose cellular tissue is situated which 

 makes the inner base of the exciple out of which asci mingled 

 with paraphyses abundantly spring. 



The spores are eight in number in each ascus ; each spore is 

 transversely divided into three or four partitions, each of which 

 contains a transparent sporule. In outline, the spore is sharply 

 elliptical. The form of the ascus is clavate with a curved or 

 hooked lower end, while the paraphyses are irregularly jointed. 



The color of the plant when it is first taken from the water 

 is of a dark tint, almost black ; but when dried it becomes 

 rather leaden, but most frequently it is rufescent, especially on 

 its under side and on the veins. This seems to be owing to a 

 pulverulent substance, which dissolves away or is set free upon 

 immersing the specimen in a mixture of sulphuric acid and 

 water, leaving the color of the plant a clear pale green, which 

 perhaps is its normal tint. The cellular, epidermal tissue, be- 

 comes then beautifully apparent, and the granules floating free 

 from the mucilage, expose the hyaline threads to full view. 



Description. Thallus foliaceous, subimbricate lacerolacin- 

 iate membranaceous, thin, smooth, fuscous-red ; beneath of the 

 same color and veined ; lobes plicate, with their margins round 

 and sinuated. Apothecia marginal, and situated in the sinus ; 



