Smooth Water Hyssop

A couple years ago I put some Smooth Water Hyssop (Bacopa monnieri), collected from a local creek, in with some of my tadpoles, various genus Rana. Unlike everything else I offered, which they only occasionally nibbled at, they eat this stuff non-stop, and metamorphosed very quickly. It turned out to be the best possible tadpole food, as it didn't break down and contaminate the water like veggies, fish flakes, and other non-living tadpole food items. It was amazing how fast a few Rana can wipe out a large mass of Water Hyssop.

This got me to wondering recently how useful this might be as a food item for certain native fish. Perhaps even protecting your ornamental aquarium plants from being too molested by certain species. Has anybody had any experience in using Water Hyssop as a food item for natives?

It seems a worthwhile thing to experiment with, which I intend to do this spring. It's easily grown in abundance and, for species that will eat it, would make a great supplement to live food. Perhaps even allowing plants that would otherwise be eaten grow in your tank.


By the way, here is a pic of some Rana eating Water Hyssop:

Interesting you found it in a local creek. B.monnieri is "supposed" to be an outer Coastal Plain plant, not in north GA, according to the Southeastern Flora Atlas: http://www.herbarium...firstviewer.htm

In NC it's mainly in tidal fresh to slighly brackish water.
You said it's easy to grow: is that in hard or soft water? strong lighting? any soil or ferts?

Anyway, I didn't know frog tadpoles ate vascular plants at all, except decaying ones.
It does seem like a good food plant and/or "sacrificial" plant to keep herbivores off your other plants.
Can you post a close-up pic so we can see this plant in more detail? flowers?

Hmm. I have Bacopa monnieri, but it doesn't look quite like that. Here's a photo: http://gallery.nanfa...er/020.JPG.html

It's slow growing, so my cladophora algae kind of colonizes it. My fish have all been carnivorous-like (I have a lot of live plants and choose my fish based on that characteristic) so nothing I've kept has ever eaten it.
My pH is 8.0 and the was is 17 degrees of hardness. This plant also grew in my tap water, which is pH 7.5 and 6 degrees of hardness.

Edited by EricaWieser, 12 January 2011 - 06:40 PM.

I should add that I bought my bacopa off of aquabid. It might be a different subspecies, I don't know where it came from.

Edited by EricaWieser, 12 January 2011 - 07:47 PM.

Hmm. I have Bacopa monnieri, but it doesn't look quite like that. Here's a photo: http://gallery.nanfa...er/020.JPG.html

It's slow growing, so my cladophora algae kind of colonizes it. My fish have all been carnivorous-like (I have a lot of live plants and choose my fish based on that characteristic) so nothing I've kept has ever eaten it.
My pH is 8.0 and the was is 17 degrees of hardness. This plant also grew in my tap water, which is pH 7.5 and 6 degrees of hardness.

That looks like the same stuff to me. I have one other photo, with a penny added for scale. I'll crop the relevant parts to show the similarity in the next few minutes. Here is the pic with the penny right after I first collected it:

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The mass of monnieri makes it look a bit different than individual strands. Here is an individual croped from the original photo.

Here is the same strand from EricaWieser's photo:


Notice in both cases how the stem leafs are in pairs stacked at 90 degrees to the previous pair. The top consist of 4 or more leafs with new growth in the center.

The differences appear to be the result of growing conditions, where EricaWieser's appears to be younger and likely in better light conditions and not so crowded. The wild conditions where I collected mine was a creek, in about 5 inches of water. The substrate was a sandy gravel with several inches of well aged leaf litter. The root system was only lightly entwined in the leaf litter and was relatively easy to separate without damage. The tops grew in a mass above the water line. This, I believe, it the primary reason for the stems in mine to be longer and lighter in color than EricaWieser's. Light simply couldn't penetrate the mass much below tops. The shading over the creek was minimal midday and medium shading mornings and evenings.

I can send a google maps location in a pm, but prefer not to in open forum.

wow wish i could get mine to grow like that....

To me, mywan's plant looks like Micranthemum umbrosum (tiny round leaves and skinny stems), not Bacopa. Erica's plant looks like Bacopa(longer leaves with wedge-shaped base and thicker stems). Maybe nativeplanter will chime in - she's the best for this sort of thing. Micranthemum would certainly be more common than Bacopa in north GA.

To me, mywan's plant looks like Micranthemum umbrosum (tiny round leaves and skinny stems), not Bacopa. Erica's plant looks like Bacopa(longer leaves with wedge-shaped base and thicker stems). Maybe nativeplanter will chime in - she's the best for this sort of thing. Micranthemum would certainly be more common than Bacopa in north GA.

You may be right here. Wasn't aware of M. umbrosum. I will investigate.

On http://www.aquascapi...php?item_id=124
It gives the leaf width of umbrosum at "about 1 inch (2 cm)". That's about 20 mm. Using the 3/4 inch penny the largest leaf width on mine is about 4 to 4.2 mm. The leaf length, on my pics, from base to leaf tip is only about 7 to 7.2 mm. So the leaf width is about 1/5th of the stated leaf width of umbrosum. Also, the pics I see of Micranthemum umbrosum shows a common root system for a mass of stems. On mine each stem had its own root system that could be separated from the rest of the mass.

Does anybody know any resources showing a more complete description? I'll be collecting more in a month or two and do much more careful observations. I'll also have a USB microscope by that time.

Edited by mywan, 13 January 2011 - 03:17 PM.

Albert Radford's Manual of the Vascular Flora of the Carolinas says M.umbrosum leaves are 3 to 7 mm; nowhere near an inch. I've seen it wild and pond-grown lots of places in NC/SC and never seen leaves any larger than 7 mm. Maybe somebody grew 20 mm leaves by forcing growth with high CO2 and ferts, or maybe PlantPedia is just wrong on leaf size.

On http://www.aquascapi...php?item_id=124
It gives the leaf width of umbrosum at "about 1 inch (2 cm)". That's about 20 mm. Using the 3/4 inch penny the largest leaf width on mine is about 4 to 4.2 mm. The leaf length, on my pics, from base to leaf tip is only about 7 to 7.2 mm. So the leaf width is about 1/5th of the stated leaf width of umbrosum. Also, the pics I see of Micranthemum umbrosum shows a common root system for a mass of stems. On mine each stem had its own root system that could be separated from the rest of the mass.

Does anybody know any resources showing a more complete description? I'll be collecting more in a month or two and do much more careful observations. I'll also have a USB microscope by that time.

Albert Radford's Manual of the Vascular Flora of the Carolinas says M.umbrosum leaves are 3 to 7 mm; nowhere near an inch. I've seen it wild and pond-grown lots of places in NC/SC and never seen leaves any larger than 7 mm. Maybe somebody grew 20 mm leaves by forcing growth with high CO2 and ferts, or maybe PlantPedia is just wrong on leaf size.

Thanks. I'll look into maybe ordering the book. I spent a few hours yesterday trying to get detailed morphology from google. The information is a bit inconsistent. The USDA site only has one picture of Micranthemum, the umbrosum here:
http://plants.usda.g...ile?symbol=MIUM
The leaf shape is most certainly wrong for that picture to be what I had. The pictures for Bacopa included caroliniana, rotundifolia and monnieri, which the leaf shape didn't fit caroliniana or rotundifolia at all either. With one very mild exception the leaf shape did fit the Bacopa monnieri here:
http://plants.usda.g...amo_005_ahp.jpg
and here:
http://plants.usda.g...amo_004_ahp.jpg
the exception seems to also apply to EricaWieser's picture.

In both cases the leaf shape is teardrop shaped. The difference is that the sides of monnieri appear slightly rounded (convex), whereas on mine the sides where slightly concave. The leafs on mine was meaty, and thick for their size, and lacked any visible veins. Your right that the range doesn't fit for monnieri though.

Perhaps, it's not unreasonable, this is a new subspecies, or possibly just morphological differences due to growing conditions. Perhaps I shouldn't have let the tadpoles eat what I collected. I intended on cultivating it in my tadpole pools, but when they eat it so veraciously I just let them. I'll be paying very special attention to this herb in the future, and contacting any county or local resources for information and help. I did find it unusual for tadpoles to so veraciously eat a live herb. They even eat the roots. I have found no reference to this anywhere. I also found it curious that several varieties of Rana, that can take multiple years the metamorphosis, all did so together within weeks of eating it. I guess I need to experiment with what other live herbs tadpoles will eat.

I zoomed in and you're right, it does look Bacopa-ish and is definitely not Micranthemum. Other possibilities to consider include: Elatine, Gratiola, or Lindernia. For current list of species check out the UNC Key to Flora of Southern & Mid-Atlantic States by Alan Weakley. It's a monster key, without pix, but good for lists of potential species IF you know the family.

http://herbarium.unc...lora2010Mar.pdf

Laura where are you? help us!

Edited by gerald, 18 January 2011 - 05:50 PM.

Sorry guys... I went on vacation for a couple days.

I'm actually thinking of Bacopa repens. Definitely not a Gratiola (although B. repens used to be called Gratiola repens)or a Micranthemum. Not the right habitat for B. monnieri. The subclasping petioles that I see look like B. repens.

I was going through survey data and believe I have a valid identification. It appears likely to be Callitriche stagnalis, common water-starwort. Here is a description:
http://www.mainevolu...erStarworts.php

The above list Georgia as native range, but the USDA site list does not. However, on the USDA site if you click Tennessee to view counties, it's found in Franklin county Tennessee. That is less than 50 miles from here. With Alabama also listed without a county map available, and the location given in Franklin county, it's likely even closer to known distributions in Alabama. Though there is a ridge cut between myself and northern Alabama, my watershed also ends up flowing into Alabama further south.
USDA site: http://plants.usda.g...ile?symbol=CAST

The keys, for which I observed, are fully accounted for with C. stagnalis. Including sizes, leaf arrangements, shapes, etc. A UK identification site has pictures that best represents what I observed (the top picture).
http://www.plant-ide...e-stagnalis.htm

I'd believe that it's Callitriche stagnalis. The images I'm seeing of it on google match your plant pretty much exactly.

The growing substrate also matches C. stagnalis.

http://www.mainevolu...erStarworts.php

Both are found in the submersed and floating leaf plant communities. Water starworts are generally found in quiet, cool (often spring-fed) waters or along muddy shores, preferring muddy or sandy substrates.

As previously described, what I collected had a root system lightly entwined in degrading leaf litter, primarily hard woods (oaks), over a sandy bottom. The creek is a tributary soon after exiting a high elevation wildlife refuge. There was a muddy barge in the creek, forming a small slow (effectively motionless) side sanctuary where tadpoles (Bufo) were in great numbers.

Here are a few of the tads I raised from that group:




Poor thing couldn't find the exit ramp:

I'm not as familiar with C. stagnalis. It's an invasive exotic, and has probably spread beyond the current distribution maps. The Callitriche that I usually see is C. heterophylla, which is just lovely when viewed from the top. Yours certainly does look like the photos I have looked at. Particularly the petiole. The leaves themselves can be quite variable in all of these species, so using the leaf shape can be difficult. But the connection between the leaf and the stem is generally not as variable.

Once again, we can thank the aquarium industry for another exotic introduction.

Ouch, I was thinking native, but that was from the C. palustris and C. heterophylla page.

Do you have any keys that would let me investigate this in more detail. If the leaf variability is an issue I would like to investigate in as much detail as possible. I'll also save some long enough to see the bloom.

I really liked the fact that I found a live plant food tadpoles liked so much. Makes keeping a clean tadpole tank a lot easier. I guess I'll keep feeding it to the tadpoles anyway. Never seen the tadpoles eat anything so voraciously.

Here is the Callitriche key from of Alan Weakley's Flora, which you can download from the UNC Herbarium website (8 MB pdf).
This key wont help you much without flowers or fruit, but at least it gives a list of possibilities to consider. I didn't realize until now about these other Callitriche besides the common C.heterophylla, which your plant clearly isn't.

Callitriche Linnaeus 1753 (Water-starwort). A genus of 20-50 species, annual and perennial herbs of aquatic, wetland, and upland habitats, nearly cosmopolitan. This genus should be included in a greatly expanded Plantaginaceae. References: Angiosperm Phylogeny Group (2003); Crow & Hellquist (2000)=Z; Fassett (1951)=Y; Erbar & Leins in Kadereit (2004). Key based on Z.

1 Flowers and young fruits with 2 inflated bracteoles at the base; leaves dimorphic (with floating rosettes of spatulate leaves and submersed linear leaves) or monomorphic.
2 Fruit margin distinctly winged, the wing nearly 0.1 mm wide, extending the entire distance from the summit to the base of the fruit; fruit globose ............................................................................................. C. stagnalis
2 Fruit margin either not winged or with a wing < 0.05 mm wide, narrowing towards the base of the fruit before ending above the base; fruit ellipsoidal, obovoid, or nearly heart-shaped.
3 Fruit as wide as long, obovoid or nearly heart-shaped ..................................... C. heterophylla var. heterophylla
3 Fruit longer than wide by > 0.2 mm, ellipsoidal ................................................................ C. palustris

1 Flowers and young fruits lacking bracts at their base; leaves monomorphic, obovate-spatulate, rounded at the tip.
4 Mericarps bent at an angle and thickened on one side at the base; [of SC southward] ........................... C. peploides
4 Mericarps not bent at an angle nor thickened at the base; [collectively widespread].
5 Fruit on pedicels 0.5-7 mm long; margin of fruit curled over on itself, appearing thickened; fruit developing underground ................................................................................................... C. pedunculosa
5 Fruit on pedicels 0.1-0.6 mm long; margin of fruit narrow, thin; fruit developing above ground ............... C. terrestris

Callitriche heterophylla Pursh var. heterophylla. Cp (DE, FL, GA, NC, SC, VA), Pd (DE, GA, NC, SC, VA), Mt (GA,
NC, SC, VA, WV): pools, slow-moving streams, ditches; common (uncommon in GA, NC, SC, and VA Piedmont, uncommon
in Mountains). March-October. Greenland west to AK, south to c. peninsular FL, TX, CA, and Mexico. The other variety, var.
bolanderi (Hegelmann) Fassett, with larger fruits, co-occurs with var. heterophylla in nw. North America and is of uncertain
taxonomic status, having been treated as species, subspecies, variety, and lumped. [< C. heterophylla – RAB, C, G, GW, S, W, WH,
Z; > C. heterophylla – F; > C. anceps Fernald – F, Y; = C. heterophylla ssp. heterophylla – K; > C. heterophylla var. heterophylla – Y]

Callitriche palustris Linnaeus. Cp (DE, VA), Pd (DE, VA), Mt (VA, WV): ponds, lakes, stagnant streams, wet soil; rare.
Circumboreal, in North America south to VA, WV, IL, TX, and CA; South America. The nomenclatural debate between C.
palustris and C. verna is difficult to resolve. [= C, F, K, S; = C. verna Linnaeus – G, W, Y, Z]

Callitriche pedunculosa Nuttall. Cp (FL, GA, NC), Pd (NC): low fields, pond shores; rare. NC, c. TN, and OK south to c.
peninsular FL, AL, and TX. [= K, WH; = C. nuttallii Torrey – GW, Y, Z]

Callitriche peploides Nuttall. Cp (FL, GA, SC): low fields, ditches; rare. April-June. SC south to s. FL, west to TX;
disjunct inland in TN, AR; e. Mexico south to Costa Rica. [= RAB, GW, K, S, WH; > C. peploides var. peploides – Y]

Callitriche stagnalis Scopoli. Pd (DE, VA), Mt (VA), Cp (VA): ponds, stagnant water, wet soil; rare, native of Europe, or
possibly also native in some areas. See Philbrick, Aakjar, & Stuckey (1998) for additional discussion of the spread of this species
in North America. [= C, F, G, K, Y, Z]

Callitriche terrestris Rafinesque emend. Torrey. Cp (DE, GA, NC, SC, VA), Pd (DE, GA, NC, SC, VA), Mt (GA, NC, SC,
VA, WV): ditches, low fields, wet paths; uncommon. April-June. MA to KS, south to GA, TX, and Mexico. [= C, GW, K, S, W,
Z; = C. deflexa A. Braun – RAB, Y; > C. deflexa var. austinii (Engelmann) Hegelmann – F, G]