54 RypBERG: Rocky MOUNTAIN FLORA 
ACERACEAE 
NEGuUNDO (Ray) Ludwig-Boehmer, Def. Pl. 508. 1760 
Professor Nieuwland in the American Midland Naturalist* 
discussed the North American species of box-elder. He used the 
name Rulac, believing in a pre-Linnaean priority for genera. As 
both the Vienna Rules and the American Code have adopted 1753 
as the starting point for botanical nomenclature, few will follow 
him in the names adopted. If our box-elders are regarded as 
generically distinct from the maples, we must use the name 
Negundo. Professor Nieuwland recognizes six species. I think 
there should be recognized eight species in North America. The 
Texan form, Rulac californica texana Pax, is well distinct from 
Negundo californicum, Professor Nieuwland having overlooked the 
difference in the fruit, which in the Texan species agrees more with 
our eastern box-elder and was included in it by Dr. Britton. 
The following key was prepared by me over two years ago and two 
new species were named in manuscript. One of these has been 
described by Professor Nieuwland under the name Rulac Nuttallii; 
a description of the other is given below. I publish here the key, 
as several of the characters have not been pointed out by Professor 
Nieuwland. 
Branches of the season glabrous or with a few scattered ap- 
ae haiis; anthers acute, tapering into a tip 4-4 
m. long, formed ad the produced connective (in the 
ae species unknow 
Fruiting pedicels pe the lower 5~8 cm. long, very 
slender: fruit glabrous, contracted below into a short 
stipe. 1. N. orizabense. 
Fruiting pedicels sparingly pilose: the lower 2-3 cm. long. 
va 
and shen finely pubescent; sal latter some- 
stricted below into a narrow stipe-like base; leaflets 
broad, toothed, rarely lobed. 
Ovary and fruit glabrous; om latter slightly or usually 
not at all constricted be 1 renee logaae 4 lobed, 
with hair-tufts in the sorte of the v 
Branches of the season densely velutinous with aa spreading 
hairs; anthers obtuse, merely mucronate. 
Leaflets coarsely dentate or lobed; re evident but short. 
Fruit distinctly constricted at th 
tipe, densely and clisnieas sie Eehir leaflets 
* Vol. 2: 129-140. 10911. ore 
2 aN. Negundo. 
3- N. Nuttallii. 
