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The apothecia, which are developed on the thallus, are the fruit bodies, 

 and contain the spores. Their form is dish-Hke, scutellaeform. They are a 

 delicate flesh-color, and on the margins are long hbrils. 



Soredia are vegetative bodies appearing on the thallus as pale green, 

 mealy-looking objects. They are composed of a few algal cells and threads 

 of hyphae. These soredia, in dry weather, are easily detached, and if con- 

 ditions are favorable, develop into lichens. 



The most common form belonging to this genus, is 



ihnea barbata (L.) Fr. v^x. florida Fr. It grows all over the world on 

 dead trees, sometimes on those which are still living, but are probably dis- 

 eased, and on old fence rails. The thallus, which is light green, is not 

 smooth, but is covered with fine points. Many lichenists call it scurfy, but 

 it is pimply, rather. From the main thallus are fine, rather stifi: fibrils. It 

 is flrmly attached to the substratum by a more or less spreading base. From 

 this it branches, giving it a shrubby appearence. The apothecia are a pale 

 flesh-color, quite large, surrounded by long greenish flbrils. While the 

 apothecia are not rare, many specimens will be found which are sterile, but 

 can be determined by the appearance of the thallus and habit of growth. 



Us}iea barbata (L.) var. \hirta Fr. is much \\\l& florida, and often grows 

 on the same tree. It can be distinguished by the soredia with which it is 

 usually thickly covered. 



L'siwa barbata (L.) Fr. var. rubii^inea Michx. is very similar to Itirta, 

 but is a dull red. In some specimens the soredia give it a silvery look. 



C's/n-a barbcta (L.) Fr. var. Ct'rat/;ui Schaev. is a pendulous species. It 

 is rather stifl: and coarse, has longer branches than florid a, and no flne 

 flbrils. 



i/siii-a barbata (L.) Fr. var. articiilata Ach. is also pendulous and light 

 green. The thallus, while not smooth, is less scurfy than the other varieties 

 of I'snca barbata. It is broken into short pieces or joints, between these 

 can be seen the medullary cord. 



Usnea angiclata Ach. as the name indicates, is angled, the thallus and 

 flbrils appearing like a miniature branch of cork elm. It is pendulous and 

 rather rigid, is a. darker, duller green than the other species of Usnca. 



Usnca tricJiodca Ach. has a soft pendulous thallus, which is a light 

 gray-green, with few branches somewhat interlaced. The apothecia are 

 small. 



I'snca longissima Ach. is a mountain species. The thallus is pendulous 

 and soft. It is pale green, the main thallus almost white, with many short, 

 flne fibrils a little darker in color. It hangs from the dead spruces in the 

 Adirondacks, three or more feet in length. After drying it is almost a 

 straw-color. 



There are a few more species of Usnca, but these given are the common 

 ones. 



Like the mosses, the different species of lichens are so closely allied that 

 it is often difficult to decide to which species a given specimen belongs. 

 After the genera are learned, every new species determined is a joy to one 

 really interested in these curious, much-neglected, but beautiful plants. 



