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the entire upper surface is reticulated, the color is dark brown, almost black. 

 The lower surface is very rough and fissured, sometimes with root-like 

 fibrils; in color it is paler than the upper side. The apothecia are small and 

 uneven in shape, and close to the surface of the thallus ; the disk is convex 

 and plicate. This species of Umbilicaria is not a common one, but is found 

 in the mountains of the Eastern and Western states, also in Europe. 



Umbilicaria Muhlenbergii (Ach.) Tuckm. Plate IX. 4. Thallus varies 

 very much in size, is sometimes very large, with one leaf which is more 

 or less folded, and torn at the margin ; it is quite rigid even when damp ; 

 color ash-gray, darker toward the margin. Beneath, the thallus is very dark, 

 and shaggy, with open net work, which at the margin divides into very 

 short, stiff fibrils. The apothecia are very numerous except at the centre; 

 they are rather large and situated in pits ; disk black, convex and plicate, in 

 finer folds than in the apothecia of some other species. This is one of the 

 lichens which bears the popular name of " Rock Tripe." 



"Umbilicaria vellea (L.) Nyl, Plate IX. 2. This is the most attractive 

 in appearance of the Umbilicarias. and when found in fruit is really beauti- 

 ful; its popular name is "Velvet Moss." The thallus is usually quite large, 

 but many specimens are small, especially those in fruit. It is one-leaved, 

 with a very irregular margin, sometimes in small scallops ; the surface is 

 smooth and powdery, is from light to dark gray in color. The lower surface 

 is a very dark brown or black, has many rigid cilia crowded together, these 

 cover the whole surface from centre to margin. The apothecia are in slight 

 depressions of the thallus, very numerous near the margin, are smaller and 

 rounder than the fruit in most of the species of Umbilicaria. This lichen 

 is found on granite rocks in the mountains, and is not often found fertile. 

 Fine specimens in fruit have been collected at Chilson Lake, Essex Co., 

 New York. 



Umbilicaria Dillenii Tuckm. Plate IX. i. This is the largest species 

 of Umbilicaria; it is found on rocks throughout the United States. Some 

 specimens grow to be nearly a foot in diameter, they are usually found 

 near water and growing closely together, often over-lapping each other. 

 The thallus is one-leaved, leathery, with an entire margin ; the lobes are 

 somewhat wrinkled. The upper surface is smooth and raised toward the 

 centre ; the color is a sooty-brown. Beneath, the thallus is very black, closely 

 covered with stiff hair-like fibrils. The apothecia, which are rare, are 

 medium and attached at the centre, are round and ridge-like. 



Umbilicaria Caroliniana Tuckm. This species is unlike the other 

 Umbilicarias in appearance, as it is not so flat and has many leaves, the 

 rounded lobes of which are very crowded ; the surface is usually papulous ; 

 in color it is a dark, dull brown. Beneath it is very black, rough and uneven ; 

 at the margin it is smooth except for a few coarse fibrils. The apothecia are 

 small but are so crowded together that they appear large. Found on rocks 

 in the mountains of North Carolina and other Southern states. 



Umbilicaria Pennsylvanica Hoffm. Thallus medium to very large, 

 one-leaved, leathery and very papulous, from dark gray to smoky-brown. 



