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LICHEN NOTES No. 4. 
A Study of Umbilicaria vellea and (Jmbilicaria spadochroa. 
G. K. Merrill. 
The statement made by Nylander (Synopsis, Pt. II, p. 9) that sterile 
specimens of U. vellea are not easily determinable, is one tp surprise an 
American student of lichens. The late Prof. Tuckerman long furnished us 
with our opinions on the taxonomy and specific delimitations of lichens, and 
his treatment of the Umbilicaria in Synopsis presented no difficulties what- 
ever, once one came to know the commoner species. Tuckerman cites only 
two species of ash-colored Umbilicaria for America, U. vellea (L.) Nyl. and 
U. hirsuta (Ach.) Stenh. Of these two, U vellea only is common, and our 
students have unhesitatingly referred all specimens of the ash-colored, whit- 
ish or brownish-ash-colored Umbilicaria, when black and hirsute below 
to this species. If, as Nylander asserts, specimens of U. vellea must be 
fertile to be identified with accuracy, it is evident that the distinguishing 
characters are apothecial, not thalline. This deduction is confirmed by the 
author’s statement of its resemblance to U. spadochroa and of a difference 
in spore measurements. The spores of U, vellea are said to measure 9-12 
by 6-7 fi, those of U. spadochroa 18-29 by 10-18/*, a very considerable discrep - 
ancy. 
Nylander credits U. vellea to Acharius, Methodus, p. 109, citing the 
amended dianogsis for the species found in Lichenographia Universalis, p. 
673, as excellent. No mention is made of U. vellea as being a Linnsean 
species, nor is allusion made to its citation in the Acharian Prodromus. 
This is the more remarkable as Acharius himself duly credits the plant to 
Linnaeus, with the synonym of Lichen velleus. It is thought that but few 
of the early lichenists rightly understood U. vellea , even Hoffman who was 
responsible for the generic name of Umbilicaria, and numbers of its species* 
miscalled and figured U. polyrrhizos for U. vellea in his Plantae Lichenosae. 
However the name figures in several of the eighteenth century floras. It is 
apparent on comparing the descriptions of U. vellea and U. spadochroa in 
the Prodromus and Methodus, that Acharius had no true conception of 
either species. The diagnoses are much alike, some of the characters at a 
later period held to distinguish the two, being used indiscriminately. 
Acharius must have been acquainted with U. vellea as found in the 
Linnaean herbarium, and it is really difficult to understand his uncertainty 
unless a word from Wainio explains, 
In a paper entitled “ Revisio lichenum in herbario Linnsei asservato- 
rium,” the latter records p. 7. that the specimens of Lichen velleus as found 
were sterile, and thus uncertain. Sterility or fertility counted for but little 
to the early species makers, the grosser differences at once apparent seem- 
ing to their minds the surer guide. While on the subject of the Acharian 
comprehension of U. vellea , it will be of interest to cite from ‘Leighton’s 
“ Monograph of the British Umbilicariae,” the results of his examination of 
authentic specimens of U. hirsuta and U. vellea , communicated by Acharius 
to Borrer, and found in the latter’s herbarium. Leighton declares that the 
