RAMALINA. 



141 



of a single species, 22. fraxinea. The thecse are somewhat 

 elongated, eight-spored, and exhibit the blue discoloration 

 with iodine. The spermogones (as occurring on var. calicaris) 

 are to be looked for with a lens on the ramifying venules of 

 the thalline lacinise, in the form of small, isolated, obtuse 

 tubercles, having a similar colour to the thallus, and which 

 closely resemble in general appearance the young apothecia. 

 They are globular or ellipsoid, and consist of a dense whitish 

 tissue, which contrasts strongly with the loose, spongy cir- 

 cumjacent medullary tissue ; the cavity is simple ; the ste- 

 rigmata delicate, simple, straight filaments closely crowded ; 

 the spermatia acrogenous and straight. The cavity of the 

 sperm ogone contains, in addition to the sterigmata, a net- 

 work of loose branching filaments, inferior in thickness, but 

 otherwise similar to the medullary tubes. 



This species has a wide geographical range ; it occurs 

 abundantly on the Himalayas and in different parts of the 

 Indian Peninsula. Species of the genus Bamalina appear 

 to be scattered all over the world, within the limits of 60° 

 north and 57° south latitude, and they extend as far north 

 as Lapland in Europe and the Polar regions in North 

 America (Dr. Hooker). The Eamalinas contain a consider- 

 able amount of gum, which has been used instead of gum- 



