116 Rhodora [JuLy 
ACER RUBRUM L. var. TRIDENS Wood, Class Book Bot. 286. (1860); 
Am. Bot. Flor. pt. 4:74. (1870); Flor. Atlant. 24. (1879); Sargent, 
Sylva N. Am. 13:11, pl. 626 (1902).— A. rubrum var. B Torrey & 
Gray, Flor. N. Am. 1:249 (1838).— A. microphyllum Pax, Bot. 
Jahrb. 7: 180 (1886).— A. semiorbiculatum Pax. l. c. 181.— A. rubrum 
subsp. microphyllum Wesmael, Bull. Soc. Bot. Belg. 29:29 (1890); 
Schwerin, Gartenfl. 42: 166 (1893) as forma — A. rubrum subspec. 
microphyllum Wesmael, |. c.; Schwerin, |. c. fig. 38, as forma; Pax, 
Engler's Pflanzenreich IV. 163:38 (1902) as forma — A. tomentosum 
Pax, Engler's Pflanzenreich IV. 163:38 (1902), not Desfontaines! 
and excl. syn. Marshall? and Kirchner? 
Differs from the type by having smaller leaves usually only 4 to 8 
cm. long and obovate in outline, three-lobed at the apex and narrowed 
from below the middle into the rounded base, usually very glaucous 
beneath and with long-persistent pubescence, and thick and firm at 
maturity. The flowers are sometimes yellow and the fruits usually 
smaller. 
MassACHUSETTS: near Auburndale, May 17, 1904, M. L. Fernald 
& Alfred Rehder. Only one rather large tree was found. "This is 
the most northern locality yet observed for the variety whose range 
extends south along the Atlantic coast through Florida into eastern 
Texas. 
In its characteristic form the variety appears well marked, but 
intermediate states are often met with and three-lobed leaves are 
occasionally found on trees of the typical form and particularly on 
stunted trees growing in swamps. In the south occurs a still more 
1The quotation Desfontaines, Tabl. Ecol. Bot. ed. 3 (1829) 136 as given by Pax 
and also in the Index Kewensis is incorrect; the name without any description 
appears only in edition 1 (1804) p. 136; in the second and third edition this name 
and likewise the preceding name A. coccineum is omitted and for these two names 
A. eriocarpum Michaux substituted. From this it may be inferred that Desfontaines 
intended the name tomentosum for A. saccharinum, but even if an herbarium specimen 
should still exist and should represent the variety tridens, the name cannot be revived 
as it is indisputably a nomen nudum, 
?'The quotation of Marshall’s A. glaucum as a synonym of A. tomentosum appears 
to be hardly more than a guess, for Marshall's very vague description does not even 
clearly show whether he had A. rubrum or A. saccharinum in mind, 
3 As Kirchner in his short description of Acer rubrum var. tomentosum (Arb. Muscav, 
186. 1864) does not mention the most obvious character, the three-lobed leaves, 
and as also Count Schwerin, who made a most careful study of the cultivated Maples, 
describes and figures it as a variety with deeply five-lobed leaves (Gartenfl. 42: 165 
fig. 50. 1893) chiefly distinguished by the persistent pubescence of the under side of 
the leaves and the intensely red flowers, I do not think it advisable to consider 
Kirchner's name as a synonym of var. tridens. 
