REV. W. A. LEIGHTON ON THE LICHENS OF ST. HELENA. 157 
P. prota (Sw.). Sterile. J.C. M. 
PANNARIA RUBIGINOSA, Del. B.,J.C. M. 
ERIODERMA UNGUIGERUM (Bor. Fée. B.,J.C. M. 
CORA PAVONTA (Web.) Sterile. B.,J.C. M. 
Two imperfect sorediate thalli, forming what were formerly termed Lepraria ochracea 
and flava. J. C. M. 
On a fragment of volcanic rock are :— Parmelia conspersa, Ach., forma Mougeotii, 
Schær. (sterile) ; another sterile Parmelia in scattered fragments, which may be possibly 
incurva, Fr.; Lecanora aurantiaca (Lightf.), forma erythrella (Ach.). B. 
The following species appear to be new and undescribed :— 
LECANORA PERSONATA, Leight., n. sp.: thallus crustaceus, albo-sulphureus, glebuloso- 
areolatus, glebulis confertis aut sepius dispersis, lobatis, subradiato-efliguratis, 
ambitu inciso-crenatis, plano-convexis, minute tuberculoso-furfuraceis; apothecia 
fusco-nigricantia, innata, plana, margine thallino integro demum excluso ; spore 8, 
incolores, oblongæ; paraphyses confertæ, distinctæ, breves, crassiuscula ; gelatina 
hymenea iodo pallide cerulescens at thecis fuscatis. 
Ad saxa volcanica. B. 
In general appearance like Z. frustulosa, Dicks, and L. argopholis (Whlnb.) ; but 
those have chemical reaction K +, C +, whilst personata has K yellow, C orange red. 
The surface of the thallus is minutely rimulose with flattened tubercles, which give it 
an amylaceous or chaffy, almost pulverulent, aspect ; but it is not really pulverulent. 
See Plate XXXV. fig. 6 a, section of thallus and apothecium ; 7 a, spores magn. 1200. 
LECIDEA APPROXIMANS, Leight., n. sp.: thallus crustaceus, tenuis, albidus vel pallide 
fuscescens, contigue rimosus, areolis subconvexis levigatis; apothecia parva, promi- 
nentia, sessilia, nigra, plana, marginata; hypothecium fuscum; spore 8, fusce, 
ellipsoidez vel oblongæ, 1-septatee; gelatina hymenea iodo intense cærulescens. 
Ad saxa volcanica. B. 
In general aspect similar to some states of L. disciformis, Fr., but differing in the 
nature of the hypothecium and the size of the spores, which approximate to those of Z. 
stellulata, Tayl., with which, however, it has no other affinity. The chemical reaction of 
the thallus is K orange, C reddish. 
See Plate XXXV. fig. 1a, thallus; 2 a, section of apothecium ; 3 a, spores magn. 1200. 
LzcrpEA LACTESCENS, Leight., n. sp.: thallus crustaceus, tenuior, albidus, lacteus, rimulo- 
sus, lzvis, areolis planis vix subconvexis; apothecia parva, prominentia, sessilia, nigro- 
fusca, plana, vix marginata, tandem convexa aut sphærica, subpedicellata, margine 
Y 2 
