TWO NEW VARIETIES OF ACER RUBRUM L.* 



Freda Detmers. 



That the species of Acer are very variable is well known and 

 that the variability has long been recognized becomes evident 

 on examination of Pax's admirable and exhaustive monograph 

 of the Aceraceae, Engler and Prantl Pflanzen Familien. I 

 have, therefore, hesitated to present two additional varieties 

 of Acer rubrum. However, these two trees are so unlike any 

 others I have seen, so unlike herbarium specimens I have 

 examined and do not conform to any descriptions given, that I 

 feel justified in describing and naming them as new varieties. 

 As Acer rubrum is dioecious the staminate trees cannot or have 

 not been verified. 



Acer rubrum L. var. viride n. var. 



Leaves thin, distinctly green on both sides, glabrous, glaucous 

 underneath with a few hairs on the veins, rather small, 5.5-7 cm. long, 

 by 7-8 cm. broad across the apices of the lateral lobes, 3-lobed with two 

 smaller lobes near the base, lobes acute, distinctly triangular, margin 

 irregularly serrate, base subcordate. The unfolding leaves somewhat 

 yellow but never red. Petioles 3-3.5 cm. long, slender, tinged with 

 red. Twigs reddish gray, glabrous. Bud scales red, glabrous, with 

 green pubescent margins. Flowers of carpellate tree with red calyx 

 and corolla, red stamens, green carpels with red styles. Mature 

 samaras distinctly green with no trace of red, glabrous, rather dull, 

 1.2-2 cm. broad, 2-2.5 cm. long; wings short, broad, strongly nerved, 

 contiguous or slightly divergent, seed cavity large, 8 by 10 mm., full 

 and plump. Fruiting pedicels green, stout, 2.5-4 cm. long. Staminate 

 tree unknown. 



The type tree is on Cranberry Island, Buckeye Lake, 

 Licking County, Ohio. It is a young specimen, about 9.5 m. 

 tall with smooth light gray bark. It is surrounded by other. 

 Red Maples. 



Type specimen in herbarium of the Department of Botany, 

 Ohio State University. Paratype in the national herbarium, 

 Washington, D. C. 



The most striking feature of the tree is its greenness. The 

 leaves develop early from 1-2 weeks before those of surrounding 

 trees and are green as soon as they unfold. The samaras are 



*Publication No. 102 from the Department of Botany, Ohio State University. 



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