ROCCELLA. 19 



As respects spore-features, the great bulk of Usneei (in obvi- 

 ous analogy with Parmelia of the next family) offers simple 

 spores, always referable to the Colourless Series except in Alec- 

 toria, in which moreover in all the species but two the spores are 

 decelerate. From this centre departs, in the same series, Kama- 

 Una with its bilocular spores ; to which the Coloured or Brown 

 Series affords no analogue. But Roccella, the next and extremest 

 type of the Colourless Series, stands in curious analogy with 

 Schizopelte of the Coloured ; whereof also Alectoria (the analogue 

 of Umbilicaria, further on) though ambiguous in most species, 

 displays finally the ultimate type. 



I. ROCCELLA, DC. 



Apothecia scutellseform, lateral, more or less adnate ; the 

 disk blackening the hymenium imposed upon a black hypo- 

 thecium. Spores dactyloid-fusiform ; quadrilocular ; colour- 

 less. Spermatia needle-shaped, bowed; upon sub-simple 

 sterigmas. Thallus fruticulose, or finally pendulous, alike 

 on both sides, cartilagiueous-coriaceous, glaucous or now 



fuscescent ; the medullary layer rather loosely cottony. 



Anatomy of the thallus given in Schwendener, TJntersuch. 



1. c. 2, p. 165, t. 6,/. 2-17. The few species, which are 



very closely akin, aud belong especially to the warmer, 

 maritime regions of the earth, constitute the famous 

 Orchella-weed of dyers. 



1. E. tinctoria, DC. ; thallus coriaceous, terete (but often more 

 or less flattened) glaucous and pale, dull ; sparingly branched but 

 much elongated, and intertangled; apothecia middling to ample, 

 sessile, disk flattish, black, equalling or excluding the margin. 



Spores fusiform-oblong, ^J mic. Ach. L. U. p. 439. Fr. L. E. 



p. 33. Schcer. Enum. p. 7. Nyl. Syn. p. 258. 



Rocks, Mexico, Krempelhuber, 1868. San Diego, California, 

 Dr. Palmer in herb. Willey. 



2. R. leucophcea, Tuckerrn. ; thallus smooth, varying from 

 pale to darker brown ; the irregular, flexuous branches com- 

 pressed and now foraminous below, but attenuated and finally 

 terete aud filiform above; apothecia middling-sized, sessile, 

 plano-convex, disk black, white-pruinose, margin thin, white. 



