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Utricularia macrorhiza

I was camping/hiking in the sierras (near Lake Tahoe) a few weeks ago and found, as I had the last year, a thriving population of Utricularia macrorhiza (aka vulgaris ssp. macrorhiza). The plants were growing in the shallow areas at the edge of a rather shallow, grassy lake.

here's some pics!

utrichabitat2.jpg


utrichabitat.jpg


utricflower2.jpg


utricflower3.jpg


utricflower4.jpg


utriccloseup.jpg

closeup of traps. Notice the black/purple colored traps in this picture and the one above it, characteristic of U. macrorhiza.

It was wonderfull for the first time to see some flowering utricularia in their natural habitat!
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Wow! Great picture! I really envy you! I have a natural pond with U.macrorhiza in it, which I visit several time a year, since 5-6 years, and I never saw any flower yet
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, neither an old flower stalk, no-thing! The shallow pond (2' at it maximum depth) is almost covered by tall trees, so there is no much light which get into the water, which can perhaps explain why these plants aren't flowering.

Again, great shot!
 
I saw some beautiful flowering specimens 5 mins from my house.  It's funny that it took me decades to even know they were there, although I thought I searched high and low.  I saw a flash of yellow this time of year back in '97 in a low shallow wetland, right at the side of the road.  I am amazed at the size of the flowers: easily the rival of any South American epiphitic species!  This year the area is thick with them: they appear reddish from an algal association.  The plants are sheathed in algae, and yet the water is pristine clear with abundant frogs and jewel weed: both indicators of a very unpolluted habitat.  Duckweed sets its roots into the algal sheath, possibly removing excess nutrients by doing so.  I use this water for my Utricularia as it is rich in microbes and small prey.  The water they grow in is at most half a meter deep, usually much less.  Last year I could not find the plants, possibly do the drought of the past 2 years.  This year, with the frequent rains, it is amazing to see how they have prospered: they literally fill the area.  I believe the population is mostly clonal, the flowers are mostly identical with scant variation.

Noah, how large were the plants you saw?  The plants here are about  1 1/2 feet long on average.
 
Hi Tamlin,

Good to hear they are flourishing in NY state as well!

The plants I saw ranged in size anywhere from 1.5 ft to large, branching specimens well over a meter in length.

Although there did seem to be some algae on the rocks, the water was mostly too cold for much algal growth. Some plants were sheathed in a layer of what appeared to be the same sediment that thickly blanketed the bottom of the lake, though it could have been partly composed of algae:

utricdust.jpg


-noah
 
Yup, thats the algae! Wow, a meter is a good sized plant from that I have seen!
 
Hi Tamlin,

You think it's algae? Based on what? (I am not questioning your judgement or anything, just interested myself
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). It could be algae, but at least part of it is sediment, as evidenced by the black granules, more visible in the picture below.

utricdust2.jpg


In the UKCP forum you stated that the algae you observed seemed to act as a sort of "sun shield", keeping the plants from being sunburned.

A second function I can see would be providing food for daphnia and other microbes which are thus lured to their deaths. I have often observed daphnia feeding on algal growth (a very thin layer on the specimens I grow) on Utricularia. My speculation is that, as they move about the plant, they would eventually inevitably end up at the trapdoor of a bladder.

Now, in cold lakes, free-floating plants likely are one of the most suitable habitats for filamentous algae, having both suitable surface area, a good amount of sunlight, and the warmth that comes from being near the water surface.

If this reasoning is correct, One could conclude that there is a kind of three-way simbiotic relationship going on between the Utricularia, the algae, and the microbial creatures, ie. daphnia. The Utricularia provides the algae with habitat and the daphnia with feeding grounds. The Aglae provides the daphnia with food and lures prey to the Utricularia. The Daphnia, in turn, both keep the algae under control, allowing the Utricularia to survive, and provide food for the Utricularia.

What do you think?

-noah
 
Noah,

There was a paper in the American Journal of Botany on U. purpurea and algae in 2001. I think they were suggesting that in this species, the living community of algae & zooplankton was more important to the plants than straightforward carnivory. Apparently U. purpurea traps few microinvertebrates, such as Daphnia, so it is the smaller organisms that are more important. Either way, I think you are right that the algae is probably beneficial.

Giles
 
Nice shots! I have been visiting CP habitat here in Michigan and have seen U. macrorhiza in flower in at least five seperate locations. I have also been fortunate enough to see U. intermedia and U. cornuta in flower as well. U. macrorhiza and U. intermedia are everywhere here in Michigan at least in the North and along the shores of the Great Lakes. I've also found U. gibba and U. minor but not in flower. I'm still looking for U. subulata, U. resupinata, U. purpurea, U. radiata and U. geminiscapa.

Everyone shoul try to get outside and visit some CPs in the wild it's a wonderful experience!
 
Hi Giles,

I read the abstract. However, in personal observations, I have seen large amount of daphnia trapped by the Utricularia. Naturally, this paper was no doubt well researched, but I do think that daphnia and similar organisms do play a large roll in the plants diet in most circumstances. Here in the "natural" artificial conditions of the water surrounding my bog and in the pond in my backyard, I have often observed traps containing upwards from 3 or 4 daphnia in them.

Though I could see the plants benefiting from algal growth inside the traps, this seems to me as more of a side effect beneficial in years of food shortage, rather than a primary food source.

Don't know if this really helps any, but I thought I'd add it.

Glenn-

[b said:
Quote[/b] ]Everyone shoul try to get outside and visit some CPs in the wild it's a wonderful experience!

That it truly is!

-noah
 
  • #10
I could only see two pics (?) but they were beautiful and fascinating. Nice job, as always, Noah.
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Interesting discussion too.
 
  • #11
PAK

I had deleted some of the pictures from my account since this discussion started in August due to space limitations, but I uploaded them again for you or others who may have missed the original posting/discussion.

As to my last comment, here is a picture of plants in my backyard, traps filled with daphnia which naturally thrive in the water that the utrics grow in.

utric.jpg


-that algae would be a more important food source than daphnia seems odd to me, considering the considerable amount of daphnia trapped by the plants. However, these conditions, it must be observed, are in my backyard, not in the wild, where daphnia sources could be considerably lower.

-noah
 
  • #12
There is a way to find out, if anyone wants a thesis. ;)  I read an abstract recently about research which used carbon isotope testing to support the hypothesis that ampullaria get much of their nutrition from leaf detritus.

Great photos!  What elevation was this lake at?
 
  • #14
I hope mine flower next year.lol Btw.do they set seed?
 
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