34 Rhodora [Marcu 
algal flora of the sublittoral belt, therefore, is largely of the type of 
the northern New England coast in summer and its winter and spring 
flora may even include spring or summer species normal to Labrador 
and Greenland coasts. The plants of the tide-pools are numerous 
in spring and even in early summer, but are few in middle and late 
summer, since the temperature of the water rises to that typical of 
the waters of Long Island Sound and those to the south without 
affording other physical conditions adapted to the growth of species 
of those regions. The tide-pool algal flora of summer, therefore, 
consists only of a few perennial species which can endure such higher 
temperatures in a state of quiescence. It is my intention to publish 
some detailed notes as to these relations when the collections have 
been more completely worked over. 
One of the interesting and important finds of our collecting was 
Dumontia filiformis (Huds.) Grev., a species, until comparatively 
recently, unknown from the Atlantic Coast of North America. At 
Newport it grows in the shallow tide-pools, often filling them com- 
pletely, and occurs from the latter part of March until the earlier 
portion of July. By the last week in March the plants were well 
formed, but no organs of reproduction were found. Presumably 
these plants were all gametophytes. About the middle of April 
plants were found with antheridia and young procarpic branches. 
About the middle of May plants with mature cystocarps were common 
as were also those with well formed but undivided tetrasporangia. 
About the middle of June only tetrasporic plants were found and 
these lasted until the middle of July in 1920, although mostly old 
and becoming disorganized. In 1921, however, on July 6, no plants 
were to be seen in the tide-pools, but there had been heavy rains for 
several days previously, which may have hastened their disappearance. 
Dumontia filiformis was first detected on the Atlantic Coast of 
North America at South Harpswell, Maine, by Grace A. Dunn, in 
June, 1913, and was collected by Roland Thaxter at Kittery Point, 
Maine, in the spring months of 1914. Plants collected by Thaxter 
in May, 1914, were distributed in the Phycotheca Boreali-Americana 
(Fasc. xliii, No. 2149) in April, 1916. In two copies examined these 
plants show young (undivided) tetrasporangia. Dunn has presented 
accounts of the vegetative structure and reproduction of the South 
Harpswell plants in two papers (Plant World, vol. 19, pp. 271—281, 
` figs. 2, 1916, and Bot. Gaz., vol. 63, pp. 425-407, pl. 19-22, and text 
fig. 1-7, 1917). 
