-85- 
here. The thallus is green on the plane upper surface and reddish 
brown below, the pigmented portion sometimes extending to the 
upper surface and forming a narrow band along the margin. The 
bulk of the thallus is made up of loose photosynthetic tissue in which 
the large air-chambers are arranged in several layers separated from 
one another by plates of cells. The chambers are bounded above by 
a thin-walled epidermis through which the boundaries of the cham- 
bers are clearly visible. Sometimes the epidermal cells develop 
small trigones but they are more frequently thin-walled throughout. 
The postical scales, which are large and imbricated, are lunulate in 
outline. Except for their hyaline margins they are deeply pigmented 
with purplish red. Each scale bears one or two appendages, com- 
posed of somewhat larger cells than the scale itself and soon becom- 
ing bleached out and transparent. The appendages are lanceolate 
and usually entire, although in some cases one or more minute and ir- 
regular teeth are present. The stalk of the carpocephalum bears a 
cluster of lanceolate scales at the base and also at the apex, similar 
to the appendages just described but larger. 
The spores in the Bic specimens, which are apparently not quite 
mature, measure about 55 in diameter and are yellowish brown. 
The spherical face presents the appearance of being coarsely tubers 
culate when seen in profile but is really covered over with low ridge- 
across which form a more or less regular reticulum with about seven 
meshes the d^'ameter of the spore. Where the spherical face meets the 
three triangular faces the ridges form a narrow wavy border about 5 /Lt 
wide. The triangular faces are not very clearly defined and bear a few 
irregular ridges which do not form a network. Each face, however, 
usually bears a ridge parallel to the border, and the three ridges by 
their coalescence form a second border much less regular and definite 
than the first. The elaters are about 10 ^ in diameter and are bluntly 
pointed at each end. Each one usually shows three brown spirals, 
which are quite distinct from one another. 
3. Neesiella RUPESTRIS (Nees) Schiffn. in Engler & Prantl, Nat. 
Pflanzenfam 1^: 32. /. 17, G-K (after Bischoff). 1893. 
Duvalia rupestris Nees, Magaz. d. Berlin. Ges. Naturf. Fr. 8 : 271. 
pi 10. 1817. Grimaldia rupestris Lindenb. Nova Acta Acad. Caes. 
Leop. Carol. 14 (suppL): 108. 1829. 
Collected in May, 1903, on soil in cavities of a limestone ledge, at 
Lemont, Illinois, by E J. Hill. The distribution of this species in 
North America is still very incompletely known. Apparently the 
first record of its occurrence was made in 1866 by Peck,^ who cited 
specimens collected by E. G. Pickett at Havana, Schuyler County, 
1. 19th Ann. Rept. Reg. Univ. State of N. Y. 65. 1866. 
