ABROTH ALLUS . 



315 



above described. Indeed the pycnides and apothecia of A. 

 Smithii are very apt to be mistaken for different states of 

 the same fructification. These pycnides are further liable 

 to be confounded with A. oxyspoms, which frequently grows 

 along with A. Smithii on P. saxatilis, and whose punctiform 

 apothecia resemble those of some Yerrucarias. A. oxysporus 

 has deplanate, immersed, scarcely prominent apothecia, with 

 pale, lanceolate, unilocular spores. We have met with it, 

 intermixed with A. Smithii, on Craigie Hill, Perth. 



2. Abrothallus Welwitzschii (named in honour of 

 M. Weiwitzsch, an accomplished Portuguese botanist). Apo- 

 thecia green-pulverulent, girt by a raised ring of the cuticle 

 of the thallus, on which they are parasitic. Spores ovate, 

 bilocular, thick, black. 



In general character this species resembles the preceding. 

 It is the var. abortiva of Sticta fuliginosa according to 

 Schserer. Specimens parasitic on S. fuliginosa, from rocks, 

 New Cut, Meadfort, Torquay, Devonshire, are contained in 

 Leigh ton's Lich. Brit. Exsicc. (No. 191, fasc. VI.) It was 

 found by Weiwitzsch on Teltigera sylvatica on the Serra de 

 Cintra mountains, Portugal; and it constitutes the cephalo- 

 dia which sometimes occur on the thallus of Sticta limbata. 



