DR. $. O. LINDBERG ON MESOTUS. 188 
recurved, and three inches high. The female inflorescence is termi- 
nal, containing about twelve pistillidia, which are slender and long- 
stipitate, as usually seen in Dicranez, the paraphyses only half 
as long, filiform, and not numerous. Very early, under the im- 
pregnated inflorescence, the stem sends out an innovation from 
the axil of the uppermost leaf (not from the axil of a bract, which 
is, I think, the prime difference between the leaves and bracts in 
acrocarpous mosses), which also soon produces a female flower at 
the very top. 
In this way the fruit is pseudolateral, just as the flower in the 
inflorescence, now called bostrya, or cyme hélicoide unipare, in the 
higher plants. The bracts forming the perichztium are twelve to 
sixteen in number, and, from a very broad base, suddenly at- 
tenuated to a subulate point; the base is nearly round, thin, 
glossy, and pellucid, concave, and convolute; the subula long, 
slender, flexuose, undulate, and carinate, with the margin densely 
and sharply serrulate, the nerve not excurrent, and also sharply 
Serrated above on the back. The basal cells are prosenchy- 
matous, incrassated, and porose between one another, the angular 
cells large, brown, rectangular, and quadrate; the upper cells of 
the base, as also the parenchyma of the point, form longitudinal 
rows, and are minute, quadrate, strongly incrassate, with very 
small, nearly stellate or angular lumen, and warted on both 
sides: but the cells of the margin form an obscure border, being 
prosenchymatous in the lower part of the subulate point, oblong- 
rounded in its upper part, and all larger, more incrassated, and 
quite smooth; this border is broadest in the upper part of the 
round base, and nowhere perfectly defined from the parenchyma 
of the bract. 
The leaves are shorter, broader, with a narrower base, less 
decidedly narrowed to the point, the areolation firmer, with more 
distinct angular cells, and the nerve nearly smooth on the back. 
The seta is very short; and no stomata could be seen on the 
theca, which is composed of irregularly rectangular quadrate, 
Strongly incrassated cells. I was unable to detect any real an- 
nulus or trabecule on the inside of the Grimmia-like teeth, 
Which are sometimes cleft at the apex. The spores are very 
large, about half the size of those in Archidium and Gigaspermum, 
Smooth, with a strong, thick exospore (besides these normal 
ones, I found numerous spores double the size, composed of six- 
teen to twenty small cells ; but having only two thece at my dis- 
