678 The Trees of Great Britain and Ireland 
VARIETIES 
The sugar maple is very variable in the wild state, and certain varieties of it 
are now recognised as distinct species by Sargent in his latest book on American 
trees. Two of these—Acer floridanum, Pax, a moderate-sized tree, growing in the 
Southern States and in Texas and Mexico, and Acer leucoderme, Small, a low tree 
ranging from North Carolina to Arkansas—would probably not be hardy if 
introduced, and need not be further mentioned by us. Acer nigrum, Michaux, 
now considered by Sargent to be a distinct species, is best treated as a variety of 
A. saccharum, and is to be carefully distinguished from var. Rugez, with which it 
has been confused. 
1. Var. nigrum, Britton, Trans. N.Y. Acad. Sct. ix. 10 (1889). 
Acer nigrum, Michaux f. Hist. Arb. Am. ii. 238, t. 16 (1810); Sargent, Garden and Forest, 
1891, p. 148, f. 27, and Trees V. Amer. 634 (1905). : 
Leaves green beneath, cordate at the base, with the basal sinus closed by the 
approximation or overlapping of the lobes; sides of the blade drooping; lobes 
usually three, occasionally five; acute, entire or obtusely toothed. Bark of old 
trees deeply furrowed, sometimes almost black. Young branchlets orange-coloured. 
This variety, according to Sargent, is widely distributed, extending from 
Ontario and the valley of the St. Lawrence, near Montreal, southward to Virginia 
and Kentucky, and westward through Michigan, Indiana, Illinois, Iowa, and 
Missouri to South Dakota and Kansas. It is comparatively rare near Montreal 
and Vermont, becoming more abundant farther west, almost replacing the type in 
Iowa, and the only form in South Dakota. It was first noticed by the younger 
Michaux on the banks of the Genesee River in New York, where it still forms a 
forest of considerable size. 
Loudon states that the black sugar maple was introduced in 1812; but it is 
now very rare in cultivation. Var. monumentale, Temple, a tree of upright 
columnar habit, occasionally seen in botanic gardens, is a form of var. nigrum. 
2. Var. Rugeli, Rehder, in Sargent, Trees N. Amer. 633 (1905). 
Acer barbatum, Michaux, Pl. Bor. Am. ii. 252 (1803). 
Acer barbatum, var. nigrum, Sargent, Silva N. Amer. ii. 99, t. gt (1892). 
Acer Rugelit, Pax, in Engler, Bot. Jahrb. vii. 243 (1886). 
Leaves pale beneath, papery in texture, three-lobed, entire or with short obtuse 
teeth. This is the common and frequently the only form of the sugar maple in the 
region from North Carolina and Georgia to Missouri; and is occasionally met with 
as far north as Michigan and Prince Edward's Island, leaves of this form sometimes 
appearing on the upper branches of trees, which bear on their lower branches 
typical leaves of the ordinary form of the species. This variety does not appear to 
be in cultivation in England. (A. H.) 
