STICTA. 91 



Looked at from the point of view of the spores, almost the 

 whole of the lichens referable here is grouped at one of the 

 extremes, the spores of Sticta, Nephroma, and Peltigera being 

 4-plurilocular, and seemingly of the Colourless Series and the 

 analogical centre of the tribe represented only, if at all, by the 

 almost rather Pannariine Erioderma. Nor is this the only 

 curious feature of the Peltigerei. Though the close affinity of 

 Sticta to Nephroma be scarcely to be questioned, or of the latter 

 to Peltigera, and the at length plainly acicular and colourless 

 spores of the last should seem to refer it, unmistakably, to the 

 Colourless Series, there is never entirely wanting some slight 

 evidence of coloration; which becomes marked in Nephroma, 

 and Sticta, and is at least observable in Erioderma. There 

 appears, however, to be little doubt entertained by authors that 

 in all these cases the spores differ in type from those of Solo- 

 rina; and 'the same view is, with some hesitation, accepted 

 here : and the genus last-named is therefore the only member 

 of the family clearly referable to the Brown Spore-series. 

 Genera, p. 31. 



XIV. STICTA (Schreb.) Fr. 



Apothecia scutellseform, sub -marginal, elevated, now 

 blackening. Spores fusiform, and acicular, 2-4-plurilocular j 

 fuscescent or without colour. Spermatia oblong, thickened 

 at the ends ; on multi-articulate sterigmas. Thallus fron- 

 dose-foliaceous, variously but for the most part wide-lobed, 

 rounded or now elongated, coriaceous-cartilagineous j villous 

 beneath, where it is commonly dotted with cyphels, or 

 marked with bare spots. Gonimous layer constituted, now 



of gonidia, and now of gonimia. Mainly a tropical genus, 



a large proportion of the species occurring also in, or con- 

 fined to austral regions, but scarcely a fifth known in the 

 northern temperate ones, where about half the prominent 

 forms occur only sterile. 



* Thallus Parmeliiform j the under side only very rarely (and 

 not at all in our species) bearing cyphels. Gonidia agreeing in 

 all important respects with those of Parmelia, and Umbilicaria. 

 Ricasolia, De Not. 



