Mutations and Evolution. 
187 
Fernald 1 describes Silene antirrhina, L. forma Deaneana as 
differing from the type only in the absence of the glutinous band 
found on some of the internodes in the type. This form is 
occasional throughout the range of the species, and is constant in 
the colonies where it occurs. A considerable number of mutations 
in wild species are given by Hus (1911), and a number of others 
have been discussed by the writer 2 in their relation to phylogeny. 
Betula nana, L. var. Michauxii , of Newfoundland and adjacent 
portions of Canada, 3 differs from the type chiefly in that the bracts 
of the pistillate aments are commonly simple and oblong instead of 
3-lobed. Similarly B. alba, L. var. elobata, Fernald, which occurs 
on Mt. Albert in Gaspe Co., Quebec, differs from the type in the 
same respect and is evidently a parallel mutation. Near New 
Boston, New Hampshire, a tree of B. lenta was found having 
deeply serrate leaves, 4 a unit variation. Laciniation of leaves and 
petals is one of the commonly recorded types of variations in plants. 
Bhamnus caroliniana, Walt, is glabrous or glabrate. The var. 
mollis, Fernald 5 differs in having its leaves densely velvety beneath. 
The pubescent variety occurs in different parts of the range of the 
species. There is no evidence as to which is the older type. In 
Erigeron ramosus the reverse change has apparently taken place. 
Var. septentrionalis. Fern, and Wieg. 6 differs in having greener 
foliage, the leaves being sparsely hispidulous or nearly glabrous, 
instead of cinereous-strigose. The glabrous variety is more 
northern than the species, occurring in Newfoundland, Eastern 
Canada, New England and Idaho. This may be because it is better 
adapted to a cold climate, or merely because it happened to arise 
in a more northern latitude, but the former seems more probable. 
A number of species have northern glabrous varieties, but in other 
species a pubescent variety of a glabrous species is more northern 
in its distribution. A somewhat different case is found in Frag aria 
Virginiana, var. terrce-novce, 1 which differs from the type in having 
the pubescence of the petioles and leaves closely appressed. The 
variety is abundant in Newfoundland, Southern Labrador, and 
the Gaspe Peninsula where the type is a rarity. It occurs as far 
1 Rhodora, 17 ; 96, 1915. Also 12 ; 129, 1910. 
1 Gates (1917c). 
3 Fernald, M. L., Rhodora, 15: 168, 1913. 
4 Sanford, S. N. F., Rhodora, 4, 83, 1902. 
6 Rhodora, 12: 79, 1910. 
6 Rhodora, 15 : 59, 1913. 
1 Fernald and Wiegand. Rhodora, 13 : 106, 1911. 
