VII. On Spheeria tartaricola, My. a new British Fungus. 
By the Rev. W. A. LEIGHTON, B.A., F.L.S., F.B.S. Edin. 
(Plate XXXV.) 
Read January 21st, 1869. 
In August 1866 I observed on the perpendicular face of the wall bounding the turnpike- 
road and the grounds of Hengwrt, near Dolgelley, North Wales, a patch of lichen about 
2 inches in diameter, which I at the time thought was Lichen candidus, E. Bot. 1138, to 
which it had a considerable general resemblance. Subsequent examination under the 
microscope proved this supposition to be incorrect, and that I had found a totally different 
thing. Regarding the thallus and the fructification as appertaining to each other, I 
could not refer my plant to any described lichen, and submitted it to Dr. W. Nylander. 
That learned lichenist replied that the thallus was that of Lecanora tartarea (Linn.), and 
that what appeared to be the fructification was in reality a Spheria growing parasitically 
on it, and which he believed to be a nova species, and requested me to figure and describe 
it under the name of Spheria tartaricola, Nyl. 
The Spheria grew in the interstices of the areolæ of the thallus (see Plate XXXV. 
fig. 1 4), and never on the surface. But on examining the latter with a lens, it was found 
to be overspread here and there with a dark filamentous radiating network, which, under 
the microscope, appeared as in fig. 2 b; but a higher power elicited that the filaments 
were composed of minute articulate irregularly oblongo-moniliform cells, each containing 
a small nucleus (see fig. 3 b), and were no doubt the mycelium of the Spheria. The peri- 
thecium was of an oblongo-conical shape, black in colour, in vertical section as fig. 4 5, 
and in structure as fig. 5 4. This contained a mass of slender paraphyses filled with minute 
granules and linear asci, containing eight spherical spores, at first colourless, and with 
iodine turning yellow (see fig. 65); but subsequently, in maturity, and when discharged 
from the ascus, of an oblong shape and a dark bright-brown colour, with a minute, paler, 
rounded nucleus in their interior (see fig. 7 b, magn. 1200). 
The only specimen observed was collected, and is deposited in the national herbarium 
at Kew. 
SPHÆRIA TARTARICOLA, Nyl. Parasitica; mycelio superficiali nigro-fusco radiante ramo- 
sissimo articulato, cellulis oblongo-moniliformibus nucleolatis; peritheciis oblongo- 
conicis nigris inter interstitia matricis conspicue protrudentibus, ascis linearibus ; 
sporidiis 8 simplicibus sphæricis vel oblongis, primo incoloribus tandem in maturi- 
tate fuscis, minute nucleolatis. 
Parasitic on thallus of Lecanora tartarea (Linn.), on a wall at Hengwrt, near Dolgelley, 
North Wales, August 6, 1866. 
y 
