Ulmaceae (elm family) Ulmus

Ulmus americana American elm

Eastern North America
Fringed samaras, a distinctive feature of the American elm; Paco Drive, Los Altos. Sairus Patel, 24 Feb 2022

American elms, much cherished in the past for their graceful vase-shaped crowns which form perfect cathedral-like canopies over streets, have been devastated by Dutch Elm Disease. A reduced specimen under the overhead power lines at 607 Paco Drive in Los Altos is the only verified one in the area. All other purported remaining examples on campus or in Palo Alto (including one at 4229 Ponce Drive, listed as a city heritage tree) have turned out to be English elms on examination. One has to wait for the right time in spring: the Americans have a delicate fringe of hairs along the edges of the flat fruits that develop rather quickly from the small flowers. The edges of the English are smooth.

Name derivation: Ulmus – classical Latin name for the elm.

About this Entry: The main text of this entry started out from the book Trees of Stanford and Environs, by Ronald Bracewell, published 2005. Entry entirely rewritten, Los Altos location added, note on pair in backyard of 579 Alvarado Row removed (no such trees were found), 966 Moreno Avenue location in Palo Alto removed (English em); all locations up to date (Aug 2023, Sairus Patel).