RIccia 27 
92-100 и) in maximum diameter, distinctly angular, with a mi- 
nutely granulate or nearly smooth margin 3-6 м width, the outer 
face lightly papillate or nearly smooth in profile, marked with close 
sinuous ridges which rarely form completely closed meshes, the 
imperfect areolae mostly 4—7 и in width, inner faces similarly but 
less strongly marked. 
Near Stanford University (Professor D. H. Campbell, Feb. 6 
and May r, 1896); on hills above Mission Dolores (534, April 
II, 1896, with R. тога and R. trichocarpa); Fort Ross, So- 
noma Co. (March 15, 1896) ; Ukiah (May 13, 1896). Collected 
by Professor Campbell also in 1893 (herb. Underwood). 
Riccia Campbelliana in its smaller forms simulates to a certain 
extent Æ. жоғе а, with which it is sometimes associated, but is 
always readily distinguished by the wider and usually longer seg- 
ments, which are commonly brown underneath, very rarely black- 
ening, by the thinner brown margins, by the larger spores and the 
elevated antheridial ostioles. Тһе epidermis, too, differs from that 
of R. шетейа, its cells being larger and commonly having their 
vertical axis longer than the horizontal, while those of R. шогейа 
are subquadrate in vertical section and are quite frequently broader 
than high, measuring 25—40 in height by 25—45% in width. 
The larger conditions of this species are somewhat suggestive 
of Riccia Bischoffii Hüben. and К. Gougetiana Mont.,* especially 
when, as sometimes happens, the thallus is rather abruptly wing- 
margined, but the Californian plant differs clearly from both these 
in being monoicous, in the usually smaller size, in the entire ab- 
sence of cilia, in the smaller, lighter colored, much more translu- 
cent spores, etc. 
Riccia lamellosa Raddi is easily distinguished from the larger 
forms of А. Campbelliana by the much more prominent scales, the 
usually less attenuate concolorous margins, the different epidermis, 
three or four layers of cells next to the dorsal surface of the 
thallus in AR. /amellosa being commonly echlorophyllose, and by 
the entire absence, so far as we have observed, of oil-bodies. A. 
lamellosa is described by Herr Stephanit as dioicous and our in- 
vestigations on Italian material point toward the same conclusion, 
though we have been able to see no antheridia. 
# We have seen an authentic specimen of this from the Montagne Herbarium 
through the courtesy of Mons. Paul Hariot of the Muséum d’ Histoire Naturelle of Paris. 
T Bull. Herb. Boiss. 6; 341. 1898. 
