What dictates the flowersize?

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Mrs.Green
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What dictates the flowersize?

Post by Mrs.Green »

Last year I bought a Notocactus uebelmanianus, in other words, it have overwintered in my care. I haven’t watered before about three weeks ago. I bought another one about three weeks ago, this was very plump ( well watered) and had two flowerbuds.

Finally getting spring, warmer weather and sun, both the ‘old’ one and the new one flowered. Both have lilac flowers.

I am a bit surprized about the difference in the flower size. Both plants are pretty much the same size but the first one is not as plump as the new one, due to less water.

The flowers on the new one is almost twice the size as on the other one. Seeing plants in nature/garden having bigger flowers when the condition is better, I would guess the same goes for cacti? Or is it more a genetic variation that plays a role? ( I am off course talking about plants of the same species here)
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anttisepp
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Re: What dictates the flowersize?

Post by anttisepp »

Dried plants have smaller flowers.
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mmcavall
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Re: What dictates the flowersize?

Post by mmcavall »

In principle I would'nt agree with Antitsepp but I can be wrong.

Dimensions and characteristics of sexual parts of a given taxa are usually more stable than vegetative parts. For example, a plant in the shade can display larger leaves when compared to its sibbilings that are growing in full sun, but the flowers will be identical. For that reason, measurements of petal size etc are important and determinant to taxonomy. Flower sizes are used to separate taxa that are very similar, for example, so I dont think this will be much subjected to environmental conditions.

Inside a given taxa, however, some variation existis. The plant description will state "petals 3.0 to 5.0 mm long" (for example). That means that a given individual or population can display petals with 3.0 while others will display petals with 5.0 mm.

That said, I believe that the variation in flower size you observe is more likely to be due to genetic diference between the plants. Not sure a water-stressed plant will produce smaller flowers, but probably less flowers (?).
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7george
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Re: What dictates the flowersize?

Post by 7george »

Well, here we need more multi-year observations about this to get to right conclusions. Notocacti live mostly in wet habitats so can take some winter watering without harm.

Number of flowers, the phase (day or hour) of anthesis also affect flower size.
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Mrs.Green
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Re: What dictates the flowersize?

Post by Mrs.Green »

Thank you Mmcavall, Anttisepp and 7george 🙂 ( beautiful flowers btw). As 7 george says, one needs a lot of trials conclude on anything. A couple of examples more from this year; In 2020 I bought a pot with 3 E.subdenutas in. They flowered next year. Clearly I didn’t spoil them when watering and they shrinked to much for my liking. Repotted them this spring and watered more but they didn’t plumped up as fast as I expected. They did flower though, even though they aborted half of the buds. The flower size this year is significantly smaller than last year, without any doubt.
LateBloomer
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Re: What dictates the flowersize?

Post by LateBloomer »

It’s a number of factors that affect flower size namely genetics. But nutrients and water are important to reach potential.

P from what I remember is most important for flower development but n and k are needed for the plant to function as a whole so are also needed.

Flowers are a large expenditure of water which is why most cactus flowers last only 1 day. A drought cactus may potentially have smaller flowers but most of the times it isn’t a large factor due to the cacti being very efficient in water usage. Day flowers however might be smaller vs night time flowers in water restricted cacti…

The difference shouldn’t be massive but don’t have much experience on this
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Hanazono
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Re: What dictates the flowersize?

Post by Hanazono »

I have kept around 300 of flowering size asterias. I do not know other species but:

Asterias are in flower from spring to autumn several times. I mean an asterias is in flower several times during this season.
Flowers in spring and summer are normal size. Flowers in autumn are small, around a haf of the normal size.
Mrs.Green
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Re: What dictates the flowersize?

Post by Mrs.Green »

LateBloomer wrote: Fri Jul 22, 2022 1:08 pm It’s a number of factors that affect flower size namely genetics. But nutrients and water are important to reach potential.

P from what I remember is most important for flower development but n and k are needed for the plant to function as a whole so are also needed.

Flowers are a large expenditure of water which is why most cactus flowers last only 1 day. A drought cactus may potentially have smaller flowers but most of the times it isn’t a large factor due to the cacti being very efficient in water usage. Day flowers however might be smaller vs night time flowers in water restricted cacti…

The difference shouldn’t be massive but don’t have much experience on this
Thank you Latebloomer 🙂 I have no doubt that genetic factors are among the ‘culprits’ here but that doesn’t explain differences when it comes to the same specimen, having difference in the flower size. I would have guessed that environmental factors as you mentions would be the key factors?
Hanazono wrote: Fri Jul 22, 2022 9:44 pm I have kept around 300 of flowering size asterias. I do not know other species but:

Asterias are in flower from spring to autumn several times. I mean an asterias is in flower several times during this season.
Flowers in spring and summer are normal size. Flowers in autumn are small, around a haf of the normal size.
Thank you Hanazono 🙂 That’s interesting. One could be tempted to belive that the plants are ‘exhausted’ after the spring/summer flowering or could ther be other factors as lower temperatures and less light? Certainly an interesting topic.
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