OF FILAMENTOUS, FRUTICULOSE, AND FOLIACEOUS LICHENS. 183 
surface; sometimes they are scattered among the apothecia; at other times they 
are met with only on specimens or thalli bearing no apothecia. The envelope 
is brown or black, and very thin, being formed of hexagonal or roundish cells. 
The internal tissue is grayish and horny ; and the body of the spermogones is 
easily enucleated with a needle. The cavity is simple, and more or less spheri- 
cal. The arthrosterigmata are longish, as in Sétecta and Collema, ramose, and 
densely aggregated into a more or less compact tissue; they are made up of 
short, roundish, or cubical cellules, which become thickened by deposits on their 
internal walls. Their length in U. pustulata is =th to ;th; their breadth varies 
from smth to month. The spermatia are rod-shaped bodies, seated on the apices 
and sides of the sterigmata ; their length is about auth to woth; their breadth 
ssmoth to santh. 
Species 1. U. pustulata, Hoffm., 
Which occurs in Europe, Africa, and northern America. It is the type of a sec- 
tion distinguished by 1-spored theca, constituting the genus Lasalia, Mér., and in- 
cluding the two following species—U. papulosa and U. Pennsylvanica. Its sper- 
mogones are usually isolated, obtuse, very prominent, black cones, round which 
the cortical or epidermic layer of the thallus is sometimes ruptured or raised ; 
their diameter is about 4th to zth. 
Specimen 1.—Vartmoor; in Herb. Hooker, Kew. The specimens from this 
station are very large,—the thallus being as handsome as in specimens collected 
by me on the Norwegian mountains, and more so than those got in the Isle of 
Skye (base of the Coolin Hills). The spermogones are abundant, but there are 
usually no apothecia. On one specimen, however, from the “ Two Tors on Dart- 
moor, near Chagford, Aug. 1836,” the apothecia, as well as the spermogones, 
abound. 
Specimen 2.—Labrador; in Herb. Hooker, Kew. Both apothecia and sper- 
mogones are plentiful and distinct. The spermatia are about yonth long, with a 
breadth of s;;th. The sterigmata are about ;,th to ;th long, with a breadth of 
muth, articulated as in Sticta or Collema. 
Specimen 3.—Sierra de Gerez, Portugal ; Wretwrirzscu, Crypt. Lusit., No. 107; 
with apothecia; in Herb. Hooker, Kew. The spermogones are superficial, large, 
distinct papillee, scattered over the pale-gray pustules of the thallus. Sometimes 
these papillee seem immersed, from being surrounded by a collar of the cortical 
layer of the thallus, which they fissure in a stellate-radiate manner. Occasionally 
the spermogones are mere immersed black points. 
Speciinen 4.—Puerto de Leiteriegos, Durieu, “Plant. select. Hisp.-Lusit.,” 
No. 58; in Herb. Hooker, Kew. Apothecia are plentiful; the spermogones are 
‘scattered about the margins of the pale-gray thallus as large, distinct, black 
papille, with a distinct round or regular ostiole. 
