` 1918] Fernald,— Validity of Limosella sibulata 161 
This plant, L. aquatica, with definite leaf-blades has a pronounced 
rosette-habit, forming ordinarily circular rosettes with the branches 
decumbent and producing tufts of leaves and numerous flowers at the 
tips and sometimes again proliferating. In wet habitats the species 
roots freely at these points of proliferation, but the specimens from 
Europe, as well as from western America, all show that the individual 
plants are fairly circumscribed and do not creep extensively. Euro- 
pean plates such as those of Reichenbach; Flora Danica (table 69) 
or Sowerby ? excellently display the habit and foliage of L. aquatica. 
‘The plant in Europe, as well as in North America, occurs in fresh soils, 
chiefly in sandy margins of lakes and ponds, or, as expressed by Syme, 
“places where water has lain in winter.” The plant of the Atlantic 
seaboard of North America, on the other hand, has absolutely no 
leaf-blade, the leaves being filiform or nearly terete; and the plant 
has a very closely repent, matted habit, forming dense turf, with the 
closely creeping stolons setting under favorable circumstances lines 
of new tufts, often extending in rows some decimeters away from the 
parent rosette. The plant is so closely repent that it is impossible 
in the material from the Atlantic seaboard to find any specimens in 
which the tufts of foliage are not conspicuously rooting at base and the 
plant is usually so matted as to form a turf almost impossible of dis- 
entanglement. This closely matted or creeping plant of Atlantic 
America is found strictly in saline or subsaline soils, always on the 
coast, the only specimens from inland stations coming from points 
not further than one or two miles from the sea. 
It would therefore seem very improbable that the plant of eastern 
America, from Newfoundland and the lower St. Lawrence to New 
Jersey and eastern Pennsylvania, is conspecific with the plant of 
quite different habit, which is so widely spread in fresh habitats over 
Europe and western America. Many attempts have been made in 
the past to separate our coastal plant, but, so far as the writer can 
find, these have all proved unconvincing, and the Atlantic coast plant 
has been left in all recent treatments either as L. aquatica or as the 
European dwarfed var. tenuifolia. The first attempts to distinguish 
the American from the European plant were made early in the last 
century when the species was discovered in southern New England 
and on the lower Delaware. In 1816 Messrs. H. N. Fenn and M. C. ° 
1 Reichenbach, Ic. Fl. Germ. xx. tab. 1722 (1862). 
2 Sowerby, Engl. Bot. ed. Syme, vi. tab. 968 (1873). 
