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Dioecious

Posted: Mon May 10, 2021 7:52 pm
by iann
The word for this week is dioecious, referring to plants that have two separate sexes. This is fairly common, but not in cacti. Some populations of Echinocereus coccineus are considered to be functionally dioecious, meaning all the flowers have both male and female parts but particular flowers are functionally different and only behave either as male or female.

Here is an example of a functionally female flower. It has anthers but doesn't make any pollen. AG11 again.
ag11-0503a.jpg
Functionally male flowers are harder to spot because they produce pollen and have anthers, but don't actually produce any seed when they're pollinated. This flower did have a stigma but it has aborted and now appears to be male. Not sure if that is a one-off or it is being functionally male.
coccineus-0510.jpg

Re: Dioecious

Posted: Tue May 11, 2021 8:27 am
by Tishania
Thank you, I was unaware of this in cacti.
You live and learn.

Ed

Re: Dioecious

Posted: Tue May 11, 2021 10:25 am
by habanerocat
There's a guy on Facebook that posts about all this kind of stuff on "cold hardy cacti". He was a website also:

http://www.stoneycreekcacti.com/

All get very complicated when he starts talking about triploids and tetraploids, but interesting none the less.
Doesn't post outside the US unfortunately.

Re: Dioecious

Posted: Tue May 11, 2021 12:21 pm
by juster
That’s really interesting Iann, thanks for explaining it so clearly and with the flowers to illustrate (tu)

Re: Dioecious

Posted: Tue May 11, 2021 12:48 pm
by Paul in Essex
Here a good example of dioecious - Dasylirion acrotriche. I have a few planted out around the garden and these two flowered the same year.

First is male:
dasyhere1.jpg
dasyhere2.jpg
And female.
dasyhere3.jpg
dasyhere4.jpg
Flowers are individually very small but iof you zoom inyou can see the yellow of the pollen bearing anthers of the male - which gives the whole spike a bright yellow colour - and the paler sigma of the females.

Interesting to note that it set viable seed here :)

Solitary female plants will develop seed capsules but these contain no seed - a source of confusion and disappointment if you are expecting seed!

Re: Dioecious

Posted: Tue May 11, 2021 2:04 pm
by Tina
You also have the unique Dorstenia Lavranni that out of all the Dorstenia family is Dioecious.

I did an article many years ago https://northants.bcss.org.uk/nl222/nl222dorstenia.htm

Re: Dioecious

Posted: Tue May 11, 2021 5:45 pm
by edds
My only dioecious plants I can think of are my Ginkgos (other than self-sown hollies in a hedge!). They also are the only plants (I believe) with motile sperm!

Re: Dioecious

Posted: Tue May 11, 2021 5:55 pm
by fero
Hi Edds
I believe cycads also have it. If you go back far enough. life is pretty much all related :grin:

Re: Dioecious

Posted: Tue May 11, 2021 6:03 pm
by Tina
Isn't it mostly males gingkoes that are in cultivation, someone planned well.

Re: Dioecious

Posted: Tue May 11, 2021 6:18 pm
by Paul in Essex
Tina wrote: Tue May 11, 2021 6:03 pm Isn't it mostly males gingkoes that are in cultivation, someone planned well.
I found out why first hand last year. On the route of one of the walks I did there is an avenue of old Ginkgo trees. One of them was a female that had littered the pavement with fallen ripe fruit. I had read that the smell was disagreeable but, of course, had to have a go myself. I can only commend to anyone NOT to be as silly as I was as it is hands down the most horrible thing I have ever smelled and it strayed in my nose for ages afterwards.

Long ago in a Galaxy far away, when I was a copper, I encountered a homeless person who had clearly not bathed for several weeks. He had also additionally been doubly incontinent. But worst of all was the abcess on his leg that had practically gone all the way through - no idea how he could have remained standing. Rotting flesh has an aroma all of its own. And that unique cocktail was the nearest I have come to this Ginkgo fruit.