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Squamellaria (was Hydnophytum) kajewskii is heterostylous


Stone Jaguar

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I have recently had the opportunity to examine and compare the open flowers at anthesis on both of the larger, seed-grown Hydnophytum kajewskii that I have growing in my collection in California. Most fortuitously from my perspective, it seems that I have two different flower morphs restricted to each of the plants, longistyle and brevistyle. Of perhaps greater interest than the confirmation that this enigmatic species is heterostylous (not entirely a surprise given the numbers of New Guinea Myrmecodia spp. now known to be) is the fact that the plants actually appear to be functionally dioecious; i.e. the stigmas are quite vestigial on the brevistyle flowers, while anthers appear to be absent or very vestigial in the longistyle flowers that I have examined thus far. This differs materially from my observations of dissected flowers of several heterostylous Myrmecodia spp. that have fully functional male and female flower parts, but are naturally self infertile for a variety of reasons.

I have attached a couple of reasonably clear photos taken with my phone over the past several days illustrating both flower forms, with a brevistyle flower split to show the club-like stigma low down in the corolla tube with the flower at anthesis and shedding pollen and a longistyle flower with a conspicuously lobed stigma. These flowers are, like most Hydnophyum flowers, very epehemeral, so almost daily inspection is required to encounter an open flower.

Growers interested in breeding this species should take note that a minimum of several plants should be acquired if one is to have a sporting chance of ending up with both flower forms. In my case, it was pure good fortune, although I do have a large 2015 seedling as backup.

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post-61-0-36924100-1447087155_thumb.jpg

I have not yet flowered H. guppyanum, but would be quite surprised if it doesn't share this trait.

Cheers,

J

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Bonjour

 

difficult to see, if indeed there are brévistyle and longistyle  flowers.

 

we would have more macro photos to see the style length .

 

hard to say that a plant dioecious is  heterostyled or otherwise , for me it is 2 different thing .

 

http://www.svtauclairjj.fr/primula/distylie.htm

 

http://www.svtauclairjj.fr/primula/genetique.htm

 

heterostyly for me is a question of compatibility with the insect, for the fertilization.

 

http://www.svtauclairjj.fr/primula/allopollinisation.htm

 

all these documents are in french desolate

 

 

jeff

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Hi, Jeff.

 

As the flowering season progresses, I will post photos of dissected flowers of both forms to provide more clarity. You can, however, clearly see that the style in the lower image exceeds the length of the corolla tube to present the stigma lobes well free of the open flower and that no anthers are visible.

 

I understand that dioecy and heterostyly are quite different concepts. When I stated that these plants may be functionally dioecious, I was referring to the flower morphology that suggests that these plants have - for all intents and purposes - unisexual flowers if both anthers in longistyle flowers and stigmas in brevistyle flowers are vestigial and physically incapable of being exploited in manual self-pollination

 

In the flowers that I have dissected from several heterostylous Myrmecodia spp. so far, the stigmas and anthers within a single flower are always fully developed and functional, but use spatial, timing, chemical, and dichotomous pollen barriers - or combinations of some/all of these - to prevent auto-fertilization. It remains to be seen whether any of these species are self-compatible when carefully hand-pollinated. Hopefully, I'll let you know soon.

 

J

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Bonjour

 

we know insects, making the pollination; ants or some others ?

 

here http://www.svtauclairjj.fr/primula/allopollinisation.htm

we have a good idea to the process.

(difficult to replicate this process manually)

 

have you on the same plants some brevistyle and longistyle flowers ? may be some hermaphrodite flower or others systems?

 

jeff

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  • 1 month later...

Hi.

 

An updated image of a "female" flower taken this week. I examined several of these under a loupe yesterday and saw no evidence of anthers anywhere in the corolla. I have not dissected any of these flowers yet since I am exploiting them to try and produce fruit next year, but increasingly suspect that this species is indeed dioecious, not distylous. The conspicuous "hairs" on the corolla throat are shared with a couple of other unidentified Hydnophytum spp. that I grow that also have interesting caudexes.

 

"Female" flowers are reasonably long-lasting for my experience with the genus at three to four days. "Male" flowers last only a day or two and produce copious amounts of dusty, golden-yellow pollen at midday on the first day. Given the location of the inflorescences on the ends of the branches and the long corolla tubes, I wonder whether this species is pollinated by a small butterfly or moth. I need to check for fragrance on the flowers at midday and evening.

 

Jeff; flower type is consistent on both plants, i.e. all of the flowers on this plant are "female", all of the flowers on the other plant are "male".

 

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Unlike other hydnophytines (except H. guppyanum), this species will permit ready observation of fruit development, assuming that I am successful in my manual pollination efforts.

 

J

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  • 4 weeks later...

Greetings.

 

I thought an update on flowering observations and first pollination attempts of this species might be of interest.

 

Thus far, over the past month a number of "female" flowers have been manually-pollinated using fresh and refrigerated pollen and a very fine camel hair water color brush. No flowers that have not been hand-pollinated, of either plant I'm working with, show evidence of successful pollination. Earliest attempts show clear evidence of fruit development at ~30 days post hand-pollination. From past availability of wild collected seed from East New Britain, I'm guessing that ripening times will be ~120 days.

 

First green fruit. Photo taken yesterday.

 

post-61-0-54336800-1451930316_thumb.jpg

 

Cheers,

 

J

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  • Frank changed the title to Squamellaria (was Hydnophytum) kajewskii is heterostylous

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