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Collected in March, 1914, at Austin, Texas, by Miss M. S. Young (No. 2; 
specimen in the herbarium of the New York Botanical Garden); also at College 
Station, Texas, by C. H. Farr. New to America. This rare species was dis- 
covered by J. Ralfs, in 1830, at Aberffraw, on the island of Angelsey in Wales, 
and is now known in addition from the English counties of Cornwall, Lancaster 
and York and from the Irish counties of Dublin, Kerry and Londonderry. For 
a long time it was supposed to be confined to the British Isles, but about fifty 
years after its original discovery it was found by Trabut at various localities 
in the vicinity of Algiers. He described it as a new species, under the name 
Fossombronia corbulaeformis, but the identity of his plant with the Petalophyllum 
was soon recognized. Largely through the studies of Massalongo the species 
is now known also from the following islands in the Mediterranean: Pianosa 
(Tuscan Archipelago), Sardinia, Sicily, Lampedusa (southwest of Sicily), and 
Malta. Its discovery in America marks a very interesting extension of range. 
The genus Petalophyllum , as originally proposed, contained only two species, 
P. Ralfsii and the Australian P. Preissii Gottsche. The latter is apparently 
as rare as P. Ralfsii , although its known range now includes New Zealand. When 
Stephani monographed the genus in 1900 1 he still recognized the two original 
species but no others. Since that time, however, he has proposed a third species, 
under the name P. bolivianum . 2 This species presumably came from Bolivia, 
although he describes the habitat as “sine loco natali.” It is unfortunately 
known in sterile condition only, but the description indicates that it must be 
close to P. Ralfsii. For descriptions of P. Ralfsii reference may be made to the 
European manuals and to an important morphological study by Cavers. 3 This 
work has served as the basis for most of the remarks which follow. 
The gametophyte consists of a green, flattened, thalloid stem about 1 cm. 
long, which is sometimes simple and sometimes once-dichotomous. This stem 
broadens out from a cylindrical stalk-like base and lies closely appressed to the 
surface of the soil. It consists of a thickened median portion, which forms a 
long convex ridge on the ventral surface, and two wings which thin out gradually, 
becoming only one cell thick in the outer part. On the upper surface of the 
wings a series of oblique lamellae, which are regarded as leaves, take their origin. 
These lamellae are only one cell thick and are usually somewhat imbricated. 
They are broadest in the middle, where they attain a width of about twenty cells, 
and narrow gradually toward each end. The lamellae on one wing tend to 
alternate with those of the other, but there are often deviations from this arrange- 
ment; two or more lamellae on the same wing, for example, may be “joined 
by a membranous outgrowth,” or two lamellae of opposite wings may be con- 
tinuous with each other across the middle. On the lower surface the stem “bears 
numerous small scales in two longitudinal rows.” These are developed early 
1 Mem. Herb. Boissier 16 : 16. 1900. 
2 Sp. Hepat. 6: 70. 1917. 
3 Notes on Yorkshire Bryophytes. 1. Petalophyllum Ralfsii. Naturalist 1903: 327-J34- 
/. 1-4. 
