Ostrya knowltonii Cov.: Knowlton hophornbeam, ironwood

Betulaceae


Distinguishing Characteristics:

Leaves: alternate, simple, deciduous, elliptic; less than 5.1 cm long; double serrate, soft-pubescent, especially below

Flowers: catkins

Fruit: conelike or hop-like cluster of nutlets, each in a papery bladder; less than 3.8 cm long

Bark: long thin shreds

Range: rare; in canyons 1220-2135 m W. Texas to S. Utah; in Az. only in W. Fork Oak Cr. and Grand Canyon

Importance: only western representative of Ostrya with only one eastern species; "ecological relict?" very hard wood

Best Recognized Features:

1. Bladder-like fruit in hop-like cluster

2. Double-serrate, soft pubescent leaves

3. Shreddy peeling bark



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