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Aquatic Plant ID

Started by Isaac Szabo , Oct 16 2014 10:14 PM

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21 replies to this topic

#1 Isaac Szabo

NANFA Member

Marble Falls, AR

Posted 16 October 2014 - 10:14 PM

Can anyone help ID this plant from Salt Springs, FL? Is it hydrilla? Click the photo for a much larger version.

Posted Image

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#2 Guest_jetajockey_*

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Posted 17 October 2014 - 03:00 AM

I don't see a photo.

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#3 Isaac Szabo

NANFA Member

Marble Falls, AR

Posted 17 October 2014 - 06:26 PM

Are others not seeing the photo? It shows up for me on my computer and phone, but maybe the file is too large for some? Here is a small version:

Posted Image

Here is a link to the full size image: http://www.isaacszab...FA/Hydrilla.jpg

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#4 Michael Wolfe

Board of Directors

North Georgia, Oconee River Drainage

Posted 17 October 2014 - 06:30 PM

I can see it both times... it was a large file and was not showing well on my phone... but eventually did... I think just a slow download.

Either write something worth reading or do something worth writing. - Benjamin Franklin

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#5 Guest_gerald_*

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Posted 17 October 2014 - 06:52 PM

A shot of a single strand would be more helpful, but my gut impression is Egeria ("Anacharis"), not Hydrilla. The other possibility is native Elodea, but it looks bigger than Elodea I have seen.

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#6 Guest_Skipjack_*

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Posted 17 October 2014 - 07:30 PM

If you click on the first image Gerald, It expands to a point where you can almost see single strands, Just in case you missed it. Issac provided a huge photo file.

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#7 Isaac Szabo

NANFA Member

Marble Falls, AR

Posted 18 October 2014 - 04:19 AM

Yes, and there's also a direct link to the large file at the bottom of my second post. I was hoping the large file would provide enough detail for a positive ID. I'm fairly certain that the leaves are in whorls of 5-6, which should rule out Elodea. I feel like I might be seeing some serrations on the leaves, which would indicate Hydrilla, but I'm not totally sure. Here's a (not very good) shot of what I think are it's flowers:

Posted Image

The flowers seem small to me, which would point toward Hydrilla, but I don't have enough experience with either species to really know. There are reports online that Hydrilla occurs at this location (Salt Springs, FL), but that doesn't necessarily mean that it was identified correctly or that Egeria doesn't also occur there.

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#8 Guest_gzeiger_*

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Posted 18 October 2014 - 05:17 AM

Doesn't really look anything like Elodea apart from growing upward.

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#9 Guest_gerald_*

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Posted 18 October 2014 - 11:54 AM

I tried zooming in on the BIG file but still cant find a spot that clearly shows the mid-stem whorls well enough. The growing tips are too crowded to count leaves (short nodes between whorls). Egeria should have mostly 4 leaves per whorl, but some nodes can have 5-8 leaves. I cant distinguish serrations from algae on leave edges in this pic. Egeria and Elodea have fine serrations; Hydrilla a bit coarser serrations. A fringe of filamentous algae is enough to obscure the serrations. Based on overall appearance (wide, crowded leaves) I still think its Egeria which is common throughout most of FL. There could be both Egeria and Hydrilla in there of course.

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#10 Isaac Szabo

NANFA Member

Marble Falls, AR

Posted 19 October 2014 - 12:49 AM

Thanks Gerald. I really appreciate your help. I tried to find some clearer photos of the mid-stem whorls. It seems to me that at least 5 leaves per whorl is pretty common:

Posted Image

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#11 Guest_Kanus_*

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Posted 19 October 2014 - 02:07 PM

I'm sure growth forms are probably variable just like most plants, but I will say I have never seen Hydrilla that is as densely leaved as that, at least not around here. The hydrilla I see is usually "leggier" and has longer spaces in between leaf nodes. This stuff is pretty dense, like the Elodea that is seen in pet stores. Maybe not definitive, but that's my observation.

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#12 Guest_gerald_*

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Posted 19 October 2014 - 06:40 PM

My experience and impression matches Derek's description, but we're used to seeing Hydrilla mostly in softer water in VA and NC. I guess it can grow more dense and Egeria-like in mineral-rich water. If 5 is the predominant number of leaves per whorl, that ought to be Hydrilla. In Egeria, 4 leaves per whorl is most common, although both species show considerable variation, from 3 to 8. Hydrilla has coarser teeth on the leaf edges but these pics arent sharp enough to see that.

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#13 Guest_trygon_*

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Posted 19 October 2014 - 07:50 PM

Isaac,
It looks like we're chasing the same rabbit. Who would've thought to target this stuff. Mine are about like yours.

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#14 Isaac Szabo

NANFA Member

Marble Falls, AR

Posted 19 October 2014 - 08:59 PM

Thanks Derek and Gerald. It looks like a definitive ID might not be possible from my photos. I have sent an email to the UF/IFAS Center for Aquatic and Invasive Plants, so maybe they will have some insight. The FWC manages Salts Springs for Hydrilla but not Egeria, so maybe it is known whether or not both species occur there.

Yes Bryce, I have never thought to target this stuff or that I would have a reason to learn so much about its identification. It's just a lucky coincidence that I happened to have a couple decent snapshots of it in my image archives.

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#15 Guest_trygon_*

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Posted 20 October 2014 - 07:09 AM

Me too. I'm going to try and meet with somebody from UT if he can id mine, I'll pass along his contact information.

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#16 Guest_gerald_*

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Posted 20 October 2014 - 10:42 AM

You didn't perchance pull any up from the substrate did you? Hydrilla "tubers" are diagnostic: Egeria and Elodea dont have tubers. Lots more comparative info here: http://www.cdfa.ca.g...fo/hydrilla.htm

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#17 Isaac Szabo

NANFA Member

Marble Falls, AR

Posted 20 October 2014 - 10:39 PM

Thanks Gerald, but I did not observe the presence/absence of tubers. I was not trying to identify the plant at the time. I was taking pictures of fish and just happened to take a few snapshots of the vegetation since the mats were impressively large/dense. I have already studied that link and other identification resources, and I feel like I could easily identify it if I had it in hand. My photos just don't the identification characteristics very well if at all. I have come to the conclusion that the best I will get from my photos is that it is likely Hydrilla. I heard back from a Florida Hydrilla researcher who said that it is highly likely Hydrilla since it is so abundant at that site. Anyway, thanks for the help guys!

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#18 Guest_gerald_*

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Posted 21 October 2014 - 11:07 AM

I used to think that too, but I've been fooled several times collecting young or wimpy Hydrilla in soft water with whorls of 3-4, soft texture, and no tubers or turions. The key characteristics work nicely on mature plants in mineral-rich water, but that's not always the conditions when we find them. In Salt Spring they should be easy enough to distinguish.