Ulmus
by Science Staff
Not peer reviewed
Last modified: 03/19/2013
Nomenclature
Ulmus L., Sp. Pl. 225. 1753. Gen. Pl., ed. 5, 106. 1754. LECTOTYPE: Ulmus campestris L., designated by Britton & Brown (1913).
Key to the species of Ulmus
1. Leaf blades less than 7 cm...Ulmus
pumila
1. Leaf blades greater than 7 cm...2
2. Upper surfaces of leaves rough, sandpapery...4
2. Upper surfaces of leaves smooth...3
3. Samaras pubescent on the sides; inflorescences racemes;
older branches with cork-ridges...Ulmus
thomasii
3. Samaras glabrous on the sides; inflorescences fascicles;
older branches without cork-ridges...Ulmus americana
4. Older twigs with corky wings...Ulmus minor (U. procera)
4.
Older twigs lacking corky wings...5
5. Leaves ciliate; buds covered with rusty hairs; fruit
pubescent...Ulmus rubra
5. Leaves not
ciliate; buds pale-pubescent or glabrous; fruit glabrous...6
6. Young branches pubescent; fruit with the seed in the
middle...Ulmus glabra
6. Young branches
glabrous; fruit with the seed above the middle (commonly cultivated)...Ulmus
×hollandica
List of Ulmus Species
- Ulmus americana
- Ulmus glabra
- Ulmus minor
- Ulmus pumila
- Ulmus rubra
- Ulmus thomasii
- Ulmus x hollandica (U. carpinifolia × U. glabra) - excluded species