En EspaŅol
Share

Ask Mr. Smarty Plants

Mr. Smarty Plants - Mexican Sycamore trees grown from seed

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
    
 
See a list of all Smarty Plants questions
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.

Need help with plant identification, visit the plant identification page.
 
rate this answer
1 rating

Tuesday - November 15, 2011

From: Austin, TX
Region: Southwest
Topic: Propagation, Seeds and Seeding, Trees
Title: Mexican Sycamore trees grown from seed
Answered by: Jimmy Mills

QUESTION:

If someone is selling an alleged Mexican Sycamore grown from a seed harvested from a mature tree growing in Austin, is it likely to be a TRUE Mexican Sycamore -- or has it most likely been pollinated by an AMERICAN Sycamore, such that the resulting hybrid has an unpredictable mix of M. Sycamore and A. Sycamore traits? I have wondered because when almost every such tree I've seen for sale in Austin has leaf undersides which usually seem to lack the silvery sheen [or at least whitish cast] and/or the fuzzy underside that I've always assumed was the mark of a TRUE Mexican sycamore. How can I know if I'm getting "the real deal"? Are these trees simply hybrids at best -- and not true Mexican Sycamores?

ANSWER:

You seem a little skeptical which is a good thing.

Lets learn a little more about Sycamores. The American Sycamore is Platanus occidentalis (American sycamore), and the Mexican Sycamore is Platanus mexicana.
P. occidentalis is native to the U.S., but P.mexicana is native to Mexico and therefore is not found in our NPIN Database. The Mexican sycamore has become popular in the last ten years as an introduced ornamental.

Sycamore trees are monoecious, having both pistillate (female) and staminate (male ) flowers on the same plant. However, it is doubtful that they are self-fertile,  ie. pollen from staminate flowers can not pollinate pistillate flowers on the same tree.  The trees are also wind pollinated. Since P. occidentalis and P. mexicana are closely related, it is not out of the question that they are able to cross pollinate and produce viable hybrids. So there is no way of knowing if the seed from which the tree being sold grew was the result of pollination from P. mexicana  or  from P. occidentalis. The odds of the tree being a hybrid seems pretty high unless the seed parent was growing in a grove of P. mexicana.

How can you tell the difference? One character that is easy to see is the the shape of the leaves. The link to austintreeexperts.com  says that P. occidentalis leaves are broader at the base, and will generally have an extra lobe that is lacking in P.mexicana. There are two photos on the link that show this distinction.

These two links from the Texas Forest Service have illustrations that also demonstrate this feature:

    Platanus occidentalis

    Platanus mexicana    mentions the silver underside of the leaf

Your best source of a TRUE Mexican Sycamore is to find one that was vegetatively propagated.

 

More Propagation Questions

Save and store pigeonberry seeds from Austin
July 20, 2009 - What is the best way to save and store pigeonberry seeds?
view the full question and answer

No female, hence, no squash.
September 07, 2008 - This is not a wild flower but. My grandchildren left a squash outside in a corner of a flower bed. This spring it grew. There are only male flowers, many of them, but no female, hence, no squash. Why...
view the full question and answer

Cold moist stratification of Echinacea purpurea
July 23, 2007 - I was looking at your info on Purple Coneflowers and it says: "Seed Treatment: Cold-moist stratification for two months improves germination." What is Cold-moist stratification? Thanks.
view the full question and answer

Spanish Dagger plant interfering with walkway in Ingram TX
April 09, 2010 - I have a Spanish Dagger that is now 8 feet tall and about to fall over in a walkway. Due to the danger of these very sharp tips I need to either cut down the plant or try to root in and replant. If ...
view the full question and answer

Will my Lisianthus survive the winter in Minnesota for another growing season?
March 09, 2009 - Do you know if Lisianthus plants planted one year, will come back the next year? We bought 6 gorgeous healthy plants last summer from a MN grower. We enjoyed them all last Summer and are wondering if ...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP
© 2014 Lady Bird Johnson Wildflower Center