— 55 — 
Collected in February, 1915, near Austin, Texas, by F. McAllister. The 
specimens were determined by Dr. Marshall A. Howe, of the New York Botanical 
Garden, and reported by him (under the name C. marchantioides ) at a meeting 
of the Torrey Botanical Club, held on March 31, 1915. 1 In 1887, Langlois 2 re- 
ported the species from Louisiana, but this earlier record is doubtful, and no other 
North American stations are at present known. In South America, however, it 
has been found in the vicinity of La Plata, Argentina, by C. Spegazzini. 3 Since 
the original discovery of the species by Micheli in the neighborhood of Florence, 
nearly two hundred years ago, its European range has gradually been extended, 
especially in the Mediterranean region, and it is now known from various other 
parts of Italy and also from Dalmatia, Switzerland (south of the Alps), France 
and Portugal. It has been reported also from Algeria, from the Atlantic Islands 
and from Japan. In certain parts of its range it is abundant. 
The genus Corsinia is monotypic and was placed by the older writers, in- 
cluding Leitgeb, among the Ricciaceae. At the present time its relationships 
are supposed to be with the more complex genera of the Marchantiales. Cavers 
has united it with the South American genus Boschia to form the special family 
Corsiniaceae, which occupies a position in his system between the Ricciaceae 
and Targionia. The features of the genus have been well described by European 
writers, 4 so that only the more distinctive will be noted here. 
The thallus is of a fair size, measuring 5-6 mm. in width, and its color varies 
from yellowish to bright green, without showing any traces of purplish pigmen- 
tation. It branches rather sparingly by forking and occasionally forms apical 
innovations. The photosynthetic tissue is made up of a single layer of air- 
chambers, separated by plates of cells and covered over by a thin-walled epi- 
dermis one cell thick. Each chamber communicates with the outside air by 
means of an epidermal pore, surrounded by one or two concentric rows of scarcely 
modified thin-walled cells. The floors of the chambers sometimes give rise to 
short and simple, upright green filaments, each composed of a single row of cells, 
but these filaments are often lacking altogether. The ventral scales are color- 
less and irregularly scattered; they are ovate to lunulate in outline, and each 
tapers gradually into a filamentous appendage. 
The inflorescence is usually dioicous but may be autoicous. The most 
important characters of the genus are derived from the grouping of the sexual 
organs and from the protective structures associated with them. The antheridia 
are situated in an elongated and sometimes forked cluster, occupying a median 
position on an ordinary thallus and bounded on each side by a low ridge. The 
archegonia occupy a similar position, but the groups, which are in shallow de- 
pressions, are shorter, and several are sometimes formed in rather close succession, 
showing that the formation of the archegonia does not limit the growth of the 
1 See Torreya 15: 159. 1915. 
2 Cat. PI. Basse-Louisiane 26. 1887. 
3 See Massalongo, Bull. Soc. Bot. Ital. 1917: 45. 
4 See especially Muller, Rabenhorst’s Kryptogamen-Fl. 6: 226-229. /. 142 , 143 . 1907; and 
Cavers, New Phytol. Reprint 4: 18-22. /. 8 , 9. 1911. 
