Johannes Schweinhardt

Here's an excellent paper discussing differences among rubra, alba, and nigra.
https://www.growables.org/information/TropicalFruit/documents/MulberryKentuckyCampbell.pdf

Here's a picture of the Wacissa tree.  It looks to me to be a morus nigra, although I don't know what to make of the length of the fruit.  It's possibly a hybrid of some sort.
https://web.archive.org/web/20180407202310/http://www.justfruitsandexotics.com/JFE/wp-content/uploads/2014/06/mulberry-wacissa.jpg

The deeply cordate base is not characteristic of a mature morus rubra leaf.

Thanks for the discussion.

Gabe Gordon wrote:

Johannes Schweinhardt wrote:  
If you don't mind me asking, what characteristic(s) did you use to identify what you purchased as a morus rubra?

The leaves were the first give away, very tight and sharp serrations on the edge, matte in appearance,  slightly fuzzy underneath and generally a very rough leaf alltogether. The leaf buds also look pretty spot on

https://www.extension.purdue.edu/extmedia/fnr/fnr_237.pdf

Thank you for your response.  The pubescence on the underside of the leaf is, from what I've gathered, the most important characteristic.  Your observations give me hope.  I'll ask the vendor for clarification because there is some indication on the Internet that the Wacissa mulberry is a morus nigra.  

There appear to be gaps in understanding of rubra.  I cannot find an answer as to when rubra seedlings begin to exhibit all of the important characteristics for rubra.  I don't believe the characteristic pubescence is present in young seedlings.  Furthermore, I'm not even sure it's present in young leaves.  The same goes with the serrations.  I have seen young leaves from old trees that do not have sharp serrations.  As the leaves mature through the year, I suspect the serrations become more pronounced.

The berries on the Wacissa Mulberry Tree that you linked to look correct, although possibly a bit too long.  The description of the size of the tree is generally comports with my understanding.  Morus rubra is a small tree.  The specimens I've seen at the National Arboretum were all small.

The state of morus rubra in this country is concerning.

Roy Hinkley wrote:I bought a couple from these folks in Ontario.
http://puslinchnaturallynativetrees.ca/the-plight-of-the-red-mulberry/

Thank you for that link.  They collect their own seeds from trees, which are isolated from morus alba.

Seed source:
http://puslinchnaturallynativetrees.ca/seed-origins-listing/

Gabe Gordon wrote:UPDATE: It took some searching but I have in fact found a red mulberry at a great nursery about two hours from me (they also do online business and I highly recommend them) called Just Fruits and Exotics, here’s the link for anybody else interested: https://justfruitsandexotics.com/product/wacissa-mulberry-tree/

Hello, new to the forum here.  Also looking for a morus rubra.  I have been burned several times with ordering what I thought was a morus rubra from a native nursery, only to receive an alba.  

If you don't mind me asking, what characteristic(s) did you use to identify what you purchased as a morus rubra?