R. HEBER Howe, JR.: NOMENCLATURE OF GENUS USNEA 375 
Usnea florida {. hirta (L.) Ach. I find three types of this 
sorediate and generally sterile form of U. florida preserved in 
the Linnean herbarium. One of these bears the Flora Suecica 
number of Lichen plicatus; the other two are atypical (as now 
understood). The original description is diagnostic. 
Usnea plicata (L.) Web. I find no true type specimen in the 
Linnean herbarium. A specimen, probably only a portion of the 
original plant, answering poorly to Linné’s description, is in his 
herbarium labeled Lichen hirtus, but with number 984 (the number 
of L. plicatus in Flora Suecica) written below the specimen. Thus 
with no definite type, I have endeavored to interpret the Linnean 
description, and the Dillenian plate (and his type) to which Linné 
refers and on which Linné based his Lichen plicatus. The Dil- 
lenian plate and specimen answer perfectly to the Linnean descrip- 
tion and must be considered the only sound evidence available, 
by means of which the status of Lichen plicatus L. can be settled. 
The Acharian plicata* represents the same plant and is not the 
plant often referred to as var. plicata (Hoffm.) Hue. There seems 
no doubt whatever that though plicatus L. and U. ceratina Ach. 
are synonymous (as commonly understood of late in this country 
and in Europe), we must not consider them identical, no matter 
with what plants we have since associated the names: The error 
has arisen through a misunderstanding of ceratina of Schaerer and 
ceratina of Acharius, the latter author having priority for the name. 
The Dillenian type was not determined by Acharius ceratina as 
it was by Schaerer, and as we find Crombie labeled it, and as the 
Acharian synonymy and material here figured goes to show.T 
Acharius's plicata is the same plant that Linné called Lichen 
plicatus; in other words the coarse, pendulous (partially papillo- 
sorediate but mot ‘‘asperrimo”’) species of the middle Atlantic 
States from where the American Dillenian type came (Pennsyl- 
vania), and a type locality cited by Linné as directly taken from 
Dillenius. I cannot see that we are in need of any further data. 
Usnea plicata Hoffm. is therefore also preoccupied, and in Hoff- 
man’s own herbarium, moreover, is represented, Dr. Wainio tells 
us, us, by a plant referable to florida of Fries. 
* Based on Linné and Dillenius, see Lich. Meth. 310. 
t See remarkable plate by Westring, Sven. Lafv. ae 69. 1805, showing 
complete structure 
