184 DR LAUDER LINDSAY ON THE SPERMOGONES AND PYCNIDES 
Species 2. U. papulosa, Ach., 
Which occurs in North America and in the Himalayas. It closely resembles, in 
its thallus, apothecia, and spermogones, the preceding species, and I know of no 
good distinctive marks, such as to justify their separation as species. 
Specimen 1.—British North America; United States; North Carolina; Lemet 
Mountain, Pennsylvania; in Herb. Hooker, Kew. The spermogones are plenti- 
ful as minute black papille, scattered in groups towards the periphery of the 
thallus. The spermatia are rod-shaped, jj,,th long, and sixth broad, on arthro- 
sterigmata, as in U. pustulata. 
Specimen 2.—Schooley’s Mountains, North America; July 1856; Dr A. O. 
Broo. Apothecia and spermogones abundant, but the former are chiefly 
degenerate. ‘The thallus is of a light-gray or brownish-gray tint, on which the 
minute, black, papillar spermogones are easily recognised. They appear to the 
naked eye as very small black grains, scattered all over the thallus, including its 
pustular elevations, but most abundant about the margins of the thallus. They 
more resemble the spermogones of U. polyphylla than of any other species of 
Umbilicaria. The ostioles are invisible even under the lens. The sterigmata 
are irregular in outline, and are composed of short, broad, thick-walled irregular 
cells. The spermatia are as described in No. 1. 
Species 3. U. Pennsylvanica, Ach. 
Specimen 1.— White Mountains, North America ; TucKERMANN; in Herb. 
Menzies, Royal Botanic Garden, Edinburgh. The thallus is of a pale-brown, 
darkest about its margins. The spermogones are paler than the thallus; hence 
they appear scattered abundantly about the margins of the thallus as white 
sago-like grains. They are large papillae,—among the largest spermogones I have 
met with in Umbilicaria,—and they have a distinct brown, round, or irregular 
ostiole. 
Specimen 2.—FRANKLIN’s First Journey; in Herb. Hooker, Kew. The spermo- 
gones are plentiful about the periphery of the thallus, as distinct black papille, 
with stellate-fissured ostioles. 
Species 4. U. Miihlenbergii, Ach., 
Like the two preceding species, a native of North America. This and the follow- 
ing species have 8-spored thece and simple spores. 
Specimen 1.—White Mountains, North America; TuckERMANN; in Herb, 
Menzies, Royal Botanic Garden, Edinburgh; and its var. @ alpina; with apo- 
thecia. Spermogones are plentiful about the margins of the thallus as small, 
distinct, flattish papille, of the same colour as the thallus, or not greatly darker, 
with ostioles more or less distinct. ; 

