SAPINDACEZ. 
SILVA OF NORTH AMERICA. 
11 
ACER RUBRUM, var. TRIDENS. 
Red Maple. 
LeEavEs 3-lobed at the apex, usually rounded at the base. 
Acer rubrum, var. tridens, Wood, Class Book, 286 (1860); 
Am. Bot. and Flor. pt. iv. 74; Fl. Atlant. 74. 
Acer rubrum, 8 Torrey & Gray, Fl. N. Am. i. 249 
(1838). 
Acer microphyllum, Pax, Engler Bot. Jahrb. vii. 180 
(1886). 
Acer semiorbiculatum, Pax, Engler Bot. Jahrb. vii. 181 
(1886). 
Acer rubrum, subspec. semiorbiculatum, Wesmael, Buil. 
Soc. Bot. Belg. xxix. 29 (Gen. Acer) (1890). — Schwerin, 
Gartenjlora, xlii. 166, £. 38, No. 4. 
Acer rubrum, subspec. microphyllum, Wesmael, Bull. 
Soc. Bot. Belg. xxix. 29 (Gen. Acer) (1890). — Schwerin, 
Gartenflora, xiii. 167. 
Acer rubrum, Chapman, F7. 81 (in part) (1860). — Sar- 
gent, Silva N. Am. ii. 107 (in part). — Robinson, Gray 
Syn. Fl. i. pt. i. 437 (in part). 
In the coast region of the south Atlantic and Gulf states the leaves of the Red Maple differ so 
much and often so constantly from those which are usually produced by this tree at the north, and 
which are figured on plate xciv. of this work, that a supplementary plate now seems necessary properly 
to illustrate this variable species. 
On the southern tree, which is generally smaller than the northern Red Maple, the leaves are 
normally obovate, usually narrowed from above the middle to the rounded or rarely cuneate base, three- 
lobed at the apex with acute or acuminate lobes which are simple or furnished with short lateral 
secondary lobes; they are remotely serrate except toward the base, with incurved glandular teeth, and 
are often ovate by the suppression of the lateral lobes and acute ; they are thick and firm in texture, dark 
green above, very glaucous and usually pubescent or rarely tomentose below, from two to three inches 
in length and from an inch and a half to two inches and a half in width.’ The flowers of the southern 
form are sometimes tawny-yellow in color,’ and the fruit, which is usually much smaller on this form 
than on northern trees and on the variety Drummond of the lower Mississippi basin, is rarely also 
yellow.? 
Acer rubrum, var. tridens, is distributed from southern New Jersey southward through the coast 
region and the middle districts to southern Florida, and along the Gulf coast to eastern Texas.‘ 
1 Individual leaves, similar in shape to those usually produced on 
the southern tree, can generally be found on the Red Maple at the 
north, particularly on the stunted trees which grow in swamps, 
although the majority of the leaves of this tree at the north are 
mostly ovate, with broad bases, and from three to five-lobed. 
2 Darlington, Fl, Cestr. 245. 
8 In April, 1890, I found at Meridian, Mississippi, a Red Maple 
with bright canary-yellow fruit. 
4 It was by an error, due to the fact that trees which had been 
planted were reported as growing naturally in this region, that the 
range of Acer rubrum as laid down on page 108 of the second 
volume of this work was extended to eastern Nebraska and Dakota. 
The most western station in this part of the country where the Red 
Maple is known by me to grow spontaneously is in the valley of the 
Kickapoo River in western Wisconsin (L. H. Pammel), and in a 
Tamarack swamp near La Crosse, Iowa, about seven miles from 
the Mississippi River, where it was found in the summer of 1901 
by Professor Pammel. 
