In message , Tim Tyler
writes
K wrote:
Tim Tyler writes

http://waynesword.palomar.edu/terminf1.htm
http://waynesword.palomar.edu/fruitid6.htm4

Scroll down for the pictures.

...and strip off any numbers accidentally appended to
the URLs.

Definitely female catkins. I note he says that male and female
catkins occur on different trees (both as a general statement about
mulberries in general, then further down about black mulberries
specifically) and that would explain why I can't find male catkins.

Perhaps too late for male catkins where you are.

From the same site:

``The black mulberry (Morus nigra), a monoecious tree native to western
Asia''

- http://waynesword.palomar.edu/jackfr1.htm

``The black mulberry (Morus nigra) is a dioecious tree native to
western Asia''

- http://waynesword.palomar.edu/fruitid6.htm

I suspect a copy-and-paste-o.

But you were saying that black mulberry is monoecious?
And obviously your particular tree is if you are in a
position to pinch out male catkins.

Black mulberry is always monoecious - AFAIK.

A few web sites claim it is dioecious. Maybe there
are dioecious black mulberry plants around that I
haven't heard about.

Stace says (of the genus, or rather of the pair of species Morus nigra
and Morus alba) "monoecious". Mitchell writes "occasionally some
branches entirely male".

If you go to Google Scholar you find that mulberries can be male,
female, monoecious or synoecious (hermaphrodite). I didn't find any
relevant papers accessible to non-subscribers, but bits of the
sericultural literature say that it is usually dioecious. Elsewhere it
is said that mulberries can change sex from year to year.

From all this data it's not clear how to describe the distribution of
sexes in mulberry, other than as "messy". Subtrioecious might do duty to
describe the situation, but this is word is not attested in Google.
--
Stewart Robert Hinsley
http://www.malvaceae.info/Biology/SexDistribution.html