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...da die Zweihäusigkeit der Pflanzen dazu führt, dass nur selten Früchte gebildet werden.
...as the dioecious nature of the plants means that fruits are rarely formed. (Translation: DeepL)

DaveW wrote: ↑Wed Aug 17, 2022 2:10 pm Mmcavall explains it excellently.

The name Mammilaria dioica indicates the original plant was dioecious = having effectively male or female flowers. Whether all specimens of the species or flowers show this trait is uncertain.

I did know that Gymnocalycium bueneckeri was supposedly dioecious, therefore hand pollinated my two but only one set a fruit. Therefore presumably the other was male and the fruiting one female if plants are male or female and not just the individual flowers themselves?

Graham Charles in his Gymnocalycium book says for G. bueneckeri:-

"The very large fruits are difficult to produce since pollination of flowers from both a fertile male and a female plant is needed. Even if pollen is transferred, a fruit does not always result."

Therefore really the only way you can be sure your plant is functionally female is if a fruit is produced.

Also what should be remembered whilst some are male or female flowers they may look to have both stigmas and anthers present but they may be atrophied and non functional so you may have to look hard to see if they have viable pollen on the anthers. The same applies to whether the stigma lobes are functional.

I must confess that I did not pay much attention to my "male" G. bueneckeri when it flowered but in photos the female stigma does seem to be missing so I will pay more attention next time it flowers and perhaps do a flower section.


bunekeri.jpg

mmcavall wrote: ↑Wed Aug 17, 2022 11:50 am The ADBLPs list reports self sterility/fertility but most of the self-sterile are monoicious species and will always have male and female parts in the same individual. As far as I know, dioicy is the exception and is not common in cacti. Maybe only a few examples can be cited? Or am I wrong?

Dicliny occurs when some members of a population
normally produce flowers that are unisexual instead of her-
maphroditic and has been reported in several Cactaceae
taxa. Dioecy (co-occurrence of androecious and gynoe-
cious plants) occurs in Echinocereus coccineus (Hoffmann
1992) and Opuntia stenopetala (Parfitt 1985). Gynodioecy
(consisting of hermaphroditic and gynoecious plants) has
been reported in Mammillaria dioica (Ganders and
Kennedy 1978; Parfitt 1985) and M. neopalmeri (Parfitt
1985). Trioecy (co-occurrence of androecious, gynoecious,
and hermaphroditic plants) occurs in P. pringlei (Fleming
et al. 1994) and Selenicereus innesii (Innes and Glass 1991).
Hermaphroditic, dioecious, and trioecious populations
have been documented for Opuntia robusta (Parfitt 1985;
del Castillo 1986; Hoffmann 1992).

DaveW wrote: ↑Wed Aug 17, 2022 2:10 pm Also what should be remembered whilst some are male or female flowers they may look to have both stigmas and anthers present but they may be atrophied and non functional so you may have to look hard to see if they have viable pollen on the anthers. The same applies to whether the stigma lobes are functional.

MrXeric wrote: ↑Thu Aug 18, 2022 5:00 am

mmcavall wrote: ↑Wed Aug 17, 2022 11:50 am The ADBLPs list reports self sterility/fertility but most of the self-sterile are monoicious species and will always have male and female parts in the same individual. As far as I know, dioicy is the exception and is not common in cacti. Maybe only a few examples can be cited? Or am I wrong?


The list also reports male/female sterility when observed. For example, the listing for G. buenekeri reports that both female and male sterility have been observed ("fs/ms"). Looking at the other gymnos in that section, dioecy seems to be a feature of subgenus Macrosemineum?

Interesting. I think we should ask Aymeric to explain this listing!

Because you can also find "f/fs". What would it mean ? "Fertile/female sterility"? It is self-fertile but sometimes the female part is not functioning?

MrXeric wrote: ↑Thu Aug 18, 2022 5:00 am But just searching the ADBLPS list, you'll get 34 hits for "fs/ms" (more if you search "ms" or fs" alone), so it's likely there are more dioecious species that haven't been scientifically documented.

Male sterility is a trait that I recall occuring in maize, which is a monoiceous species for sure. So male sterility (or female sterility) is not the same as dioicy, although the practical result is the same (you end needing two plants to make a cross).

DaveW wrote: ↑Sat Aug 20, 2022 11:39 am Yes in some cases the style will elongate and stigma will mature after the anthers have shed most of the viable pollen to help prevent self fertilisation, in other genera the style and stigma may be exerted first before the anthers are. Seemingly there are many versions of self sterility in plants.