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Monday - July 22, 2013

From: The Woodlands, TX
Region: Southwest
Topic: Plant Identification, Trees
Title: Plant ID from The Woodlands TX
Answered by: Barbara Medford


Your plant database does not distinguish 2 native tree species. Common names for these 2 trees: American hophornbeam and ironwood or musclewood. These common names are used for both trees - even more confusing. My question is: What is the correct Latin names for the tree with shaggy bark and the tree with smooth muscle-like bark? These trees are definitely different, but your database leaves me confused.


If you follow this plant link Carpinus caroliniana (American hornbeam) to our webpage on this plant, you will find this sentence:

"The graceful, drooping branches and slender trunk are pale gray, smooth and sinewy with twisting, muscle-like bulges." This USDA Plant Profile Map shows that the American hornbeam is native to Montgomery County.

There are six native North American trees having the common name "ironwood":

1. Carpinus caroliniana (American hornbeam) - discussed above.

2. Lyonothamnus floribundus (Catalina ironwood) - Native Distribution: Only on Santa Rose, Santa Cruz, Santa Catalina, and San Clemente Islands of California; at 500-2000 (152-610 m).

3. Lyonothamnus floribundus ssp. aspleniifolius (Fernleaf catalina ironwood) - Native Distribution: Channel Islands, CA

4. Lyonothamnus floribundus ssp. floribundus (Catalina ironwood) - Native Distribution: South Channel Islands (Santa Catalina Island), California, endemic. Threatened by feral animals.

5. Olneya tesota (Desert ironwood) - Native Distribution: S. AZ, s.e. CA, Sonora & Baja CA
Native Habitat: Foothill washes; low desert areas

6. Ostrya virginiana (Eastern hop-hornbeam) - Loose bark, in narrow, rectilinear strips, covers the often twisting trunk. USDA Plant Profile Map shows this one also native to Montgomery County.

You will notice that only the first, Carpinus caroliniana (American hornbeam), is in the Betulaceae (Birch) family. I think we are caught up in the "common name" syndrome once again. If you wish to further attempt to distinguish these trees, follow each plant link above to our webpage on that plant, scroll down to "Additional Resources" and click on the link to Google on that plant. We are betting that only Carpinus caroliniana (American hornbeam) and Ostrya virginiana (Eastern hop-hornbeam) are present where you garden, and they are not even closely related to each other.


From the Image Gallery

American hornbeam
Carpinus caroliniana

Catalina ironwood
Lyonothamnus floribundus ssp. floribundus

Desert ironwood
Olneya tesota

Eastern hop-hornbeam
Ostrya virginiana

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