Ostrya knowltonii Coville


Family: Betulaceae

Description: Relatively small trees to 10.0 m in height; bark brownish gray, broken into narrow scales; twigs and leaf petioles often cover with stalked glands (SE New Mexico); leaf blades suborbicular-ovate to ovate-elliptic, rounded to slightly cordate at base, margins sharply double-serrate, 3.0 to 5.5 cm in length and 2.5 to 5.0 cm in width; pistillate catkins a flattened bladder-like, papery husk; nutlets not winged, each enclosed in the papery bractlets; perianth absent in the staminate flowers and present in the pistillate flowers; staminate catkins 2.0 to 3.0 cm in length and pistillate catkins 1.0 to 4.5 cm (?) in length at maturity.

Distribution: Has been rarely collected in the southern one-third of New Mexico at 1,500-2,100 m (5,000-7,000 ft) in elevation. It also occurs in Texas and Arizona. Known for its extremely hard wood, it is usually found along streams and in moist canyons.

Plants Seen or Cited: ARIZ: Several sheets, however all are from the Grand Canyon area. NMSU: One collection, San Andres Mountains, north side of San Andres Peak, T.K. Todson, 19 Oct. 1975

Comments: There are several unanswered basic questions concerning speciation within the taxon in the southwest. Although labeled a single species, I am not certain the Arizona collections and the Texas collections should be considered a single species. It seems to me we need to know more about the genus in Mexico, in comparison to the genus in eastern U.S. We should protect the genus Ostrya in New Mexico.

Status: Rare in NM and with considerable disjunction from both the AZ and TX collections.

Important Literature:

Carter, J.L. 1997. Trees and shrubs of New Mexico.

Correll, D S. and M.C. Johnson. 1970. Manual of the vascular plants of Texas.

Editorial Committee. 1996. Flora of North America, Vol. 3.

Kearney, T.H. and R.H. Peebles. 1951. Arizona flora.

Martin, W.C. and C.R. Hutchins. 1980. A flora of New Mexico.

Powell, A.M. 1988. Trees and Shrubs of Trans-Pecos Texas.

Welsh, S.L., D. Atwood, S. Goodrich and L.C. Higgins. 1987. Great basin naturalist memoirs: A Utah flora.

Information Compiled By: Jack Carter, 1997