W. C. Cheng
Ulmus gaussenii W. C. Cheng, the Anhui, or Hairy, Elm, is a medium deciduous tree whose natural range is restricted to the valleys of limestone mountains in Anhui Province, eastern China. U. gaussenii is now possibly the rarest and most endangered elm species, with only approximately 30 trees known to survive in the wild.
The tree can grow to a height of about 25 m, with a slender trunk < 0.5 m d.b.h. The bark is longitudinally fissured and almost black. The glossy leaves are generally obovate, < 11 cm long, borne on densely pubescent reddish twigs, sometimes featuring flat corky wings. The wind-pollinated apetalous flowers appear in March, the large orbicular samarae < 28 mm diameter ripen in April.
Pests and diseases
In the wild, the tree is most commonly found on flood plains, indicating a tolerance of periodic inundation. The species is very rare in cultivation in West; it was introduced to the Morton Arboretum, Illinois, in 1995 as part of an evaluation of Chinese elms for landscape use. In artificial freezing tests at the arboretum  the LT50 (temp. at which 50% of tissues die) was found to be - 30.7 °C. There are no known cultivars of this taxon, nor is it known to be in commerce beyond the USA.
- North America
- Brenton Arboretum, Dallas Center, Iowa. No accession details available.
- Chicago Botanic Garden, Glencoe, Illinois. Planted in West Collections Area.
- Denver Botanic Gardens. Neither acc. no. nor origin disclosed
- Morton Arboretum. Acc. no. 49-95. Wild collected, Anhui Province, China.
- U S National Arboretum , Washington, D.C., USA. Acc. nos. 76224, 68980.
- North America
- World Conservation Monitoring Centre (1998). "Ulmus gaussenii". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 9 May 2014.
- Grimshaw, J. & Bayton, R. (2009). New Trees - Recent Introductions to Cultivation. RBG Kew, London. ISBN 978-1-84246-173-0
- Fu, L. & Jin J. (eds). (1992). China Red Data Book. Rare and endangered plants. Vol. 1. Science Press, Beijing
- Fu, L., Xin, Y. & Whittemore, A. (2002). Ulmaceae, in Wu, Z. & Raven, P. (eds) Flora of China, Vol. 5 (Ulmaceae through Basellaceae). Science Press, Beijing, and Missouri Botanical Garden Press, St. Louis, USA. 
- Ware, G. (1995). Little-known elms from China: landscape tree possibilities. Journal of Arboriculture, (Nov. 1995). International Society of Arboriculture, Champaign, Illinois, USA. 
- Shirazi, A. M. & Ware, G. H. (2004). Evaluation of New Elms from China for Cold Hardiness in Northern Latitudes. International Symposium on Asian Plant Diversity & Systematics 2004, Sakura, Japan.