18 Rhodora [JANUARY 
glabra have been referred by others to A. groenlandica; and examina- 
tion of herbarium-material shows at once that the characters depended 
upon are far from constant. Thus material of most typical A. 
groenlandica from Greenland and Labrador and the highest New 
England mountains shows sepals varying from 3-5 mm. in length, 
while plants of good A. glabra from the South (for example, Biltmore 
Herb. no. 664 from North Carolina; Curtiss, no. 304 from Nashville, 
Tennessee; and sheets from Lookout Mountain, near the line between 
Tennessee and Georgia), with pedicels up to 4.5 cm. long and with 
cauline leaves up to 3 cm. long, have sepals 3-5 mm. long, i. e. with 
the same variation in length as those of A. groenlandica. Similarly 
with the capsules: the material from Lookout Mountain, with long 
leaves and pedicels, has capsules up to 5.5 em. long, while fully ripe 
material from Table-Top Mt., Gaspé, has the capsules less than 4 mm. 
long. The stems of the boreal plant may be as freely forking as the 
austral, having 1-30 flowers, while characteristic. southern plants 
with long leaves and pedicels may have the stems subsimple or with 
only few flowers. The Lookout Mt. material collected by Judge 
Churchill has the petals as long and as broad as much of the northern 
material; and the seeds of the northern and southern specimens are 
quite alike. 
Nevertheless in spite of the absence of good specific characters in 
the seeds (which usually display the best of specific differences in 
Arenaria), in the capsules, petals and sepals, there is a “look” about 
the two extremes which indicates that they are not strictly identical. 
The boreal A. groenlandica is more tufted and lower, usually with 
more developed basal leafy shoots; its cauline leaves are shorter; 
its pedicels become less elongate, and its petals are inclined to be 
longer. This typical A. groenlandica is confined in New England and 
New York to the very highest mountains, descending along brooks 
in the White Mountains only to 885 m. and occurring on the summit 
of Mt. Monadnock, New Hampshire, above 915 m.; in Vermont it 
is only on the summits of Mansfield and Camel's Hump; in New 
York only on the summit of Whiteface. 
On the siliceous or granitic rocks of the Kittatinny Mts. in New 
Jersey, the Shawangunk and Catskill Mts. in New York, and exposed 
granitic ledges of Connecticut and southwestern Rhode Island occurs 
a plant which has always been referred to A. groenlandica. The 
writer had never had a field-acquaintance with this plant of southern 
