LINDSAY, ON ABROTHALLUS. 33 



of the amended characters of the genus Abrothallus, and of 

 the species A. Smithii and A. oxysporus, I have retained the 

 names originally bestowed on them by De Notaris and 

 Tulasne, not because I prefer them as peculiarly appropriate ; 

 but because I am averse to increase the " confusion worse 

 confounded " of licheuological nomenclature by altering old 

 and conferring new names, where it is not absolutely neces- 

 sary. A complex synonymy has too long been a stumbling 

 block to the licheuological student. 1 cannot, however, 

 omit to notice here the faultiness of the generic term origi- 

 nally proposed by De Notaris [AbrothaUus, from aijpo-, thin 

 or delicate, in allusion to a supposed thin or delicate thallus) , 

 he having mistaken deformed portions of the thallus of 

 P. saxatUis for the proper thallus of the parasite. Tulasne 

 has proposed a name, which is less objectionable, viz., 

 Phymatopsis, fi'om ^vjin, a tuber, and o'^'ts, like ; but I prefer 

 retaining the first for the reasons just stated. 



The insertion here of the amended characters of the genus 

 Abrothallus, and of the species A. Smithii and A. oxysporus, 

 — so far as based on my own researches, — will facilitate the 

 subsequent details of minute structui^e. 



Korber arranges the genus Abrothallus in the sub-family 

 Biatorinese, of the natural order Lecideacese ; and the struc- 

 ture of the apothecia appears to me to justify his classifica- 

 tion. He only, however, describes the species A. Smithii 

 and A. microspermus , the latter of which 1 shall show is to 

 be regarded as only a variety of the former ; and he removes 

 the other species described by Tu.lasne out of the genus 

 Abrothallus, from which they are distinguished by their very 

 different spores. He does not appear to have had full 

 opportunities of studying them ; for he speaks of them as 

 hitherto unobserved in Germany. Hence his decision is 

 based on insufficient grounds. 



Gen. Abrothallus, De Notaris emend. — Species athalline ; 

 parasitic on the thallus of various foliaceous lichens. Ajjo- 

 thecia developed in medullary tissue of matrix ; burst through, 

 sometimes fissuring in a radiate manner, the cortical layer, 

 which may form a raised border ; finally seated on, or par- 

 tially immersed in, the alien thallus ; at first flattened or 

 discoid, sometimes becoming puhdniform or globose ; immar- 

 ginate ; circumference agglutinated to matrix or free ; smooth 

 or pulverulent ; mostly black. Hypothecium brownish or 

 greenish. Thecce eight-spored, clavate, becoming obovate ; 

 amyloid reaction with iodine often inconspicuous or absent. 



