# Plant ID?



## Ajax

I got this plant mixed in with some HM that I bought years ago. It was always growing faster than the HM, and was impossible for me to get rid of. I finally just pulled all the HM up, & planted this one. It has been much better for me than HM ever was. Doesn't suffer from lower stem rot when it gets really bushy like HM tends to. I've also grown it as a foreground cover as well. I almost lost it when Ike hit, but I found 2 stems still alive and have kept it going. It's about 1/2" from tip to tip. Any ideas?


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## HeyPK

It looks like the two-leaved or 'Amano' variety of HM. Is similar, but probably a different species.


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## miremonster

I agree with Paul. I've got this Hemianthus too, compared to "normal" HM it is a weed...

Btw., there may be a problem with the identity of Hemianthus (or Micranthemum) micranthemoides. This species is said to be lost in its natural area since 1941: 
http://findarticles.com/p/articles/mi_m1200/is_11_161/ai_84307100/
http://fins.actwin.com/aquatic-plants/month.200203/msg00875.html
Is the common HM in the aquarium hobby actually HM?
In Florida another species occurs, Hemianthus glomeratus. Further species (not only H. callitrichoides) occur in the West Indies. Maybe there is no consensus about the species number. Till now I didn't find useful literature for determination of all the Hemianthus species. Seemingly there is no revision of the genus.


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## HeyPK

My _Hemianthus micranthemoides_, three-leaved variety, is enough like a weed. It is hard to eliminate from an aquarium because it comes back from tiny floating pieces and can grow perfectly well floating. I didn't know it was considered extinct. I think I remember seeing a bit of it growing in Black Creek in the Desoto National Forest in southeast Mississippi. I might make it down there this coming summer, and I will keep an eye out for it.

By the way, I have both the two and three leaved varieties growing emersed, and, in the past I have seen both of them flowering with microscopic flowers. This summer, when I finally get some time, I will take a look at them to see if there are any differences. _Micranthemum umbrosum_, while not abundant, can be found in ditches in the Jackson, Mississippi area.


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## miremonster

HeyPK said:


> My _Hemianthus micranthemoides_ I think I remember seeing a bit of it growing in Black Creek in the Desoto National Forest in southeast Mississippi. I might make it down there this coming summer, and I will keep an eye out for it.


 That's exciting, it would mean that You have seen a Hemianthus population outside of the documented distribution of the 2 US-american species, H. (Micranthemum) micranthemoides (Atlantic coast from NY to Virginia) and H. glomeratus (M. glomeratum) (Florida).
The drawing of H. micr. here shows a 2-leaved plant: http://plants.usda.gov/java/profile?symbol=MIMI6
and this one of H. glomeratus a 3-4-leaved plant: http://plants.ifas.ufl.edu/images/line_drawings/micglo2.jpg
Maybe these 2 species were not differentiated in former times. If the informations on the USDA site are correct, there is a distribution gap between them.


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## Cavan Allen

_H. glomeratus_ specimens do indeed look very much like _H. micranthemoides_. If the plant in the hobby is actually the latter, could it have been cultivated for so long?

I saw the actual last specimen of _H. micranthemoides_ collected on September 9th, 1941. How sad!

There was another specimen of an _H. reflexus_ from the Isle of Youth in Cuba that looked very nice. It was slightly smaller than the above two but with linear leaves. Kind of clumpy. Neat stuff, and I hope we see it some day!


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## miremonster

Interesting, thank You! Had the H. reflexus specimen flowers/fruits, or was it probably a submersed one?
I also have grown both the common HM and Hemianthus sp. "Amano's pearl grass" emersed. First in separate pots, then pieces of the latter entered the pot of the former and began overgrowing the common HM. They were distinguishable also when growing in the same pot. "Amano's" is apparently more vigorous and less demanding also in emersed cultivation.

Emersed H. sp. "Amano's pearl grass" has always decussate leaves being roundish with many short hairs on the margin and distinct dimples on the surface:









Flower:









The common H. micranthemoides(?) has whorls of 3-4 leaves also when emersed, the leaves rather oblong-ovate, somewhat lighter green, with fewer hairs, smoother surface, less prominent midrib (a somewhat hidden little shoot of "Amano's" is visible on the left):
















Flower:


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## Cavan Allen

Yes, the _H. reflexus_ looked like it was emersed. It said it was growing on the edge of a pond and was rare. Cuba looks like it would be a great place to go collecting.

The two-leaf stuff is a real mystery. If we're thinking of the same plant, I don't see it being _H. micranthemoides_. Isn't it supposed to be from Japan?

Nice photos. You must have a really good macro lens!


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## miremonster

> Nice photos. You must have a really good macro lens!


 Thank You - I was allowed to use a stereo microscope in the university of Göttingen and I've put my simple digital cam on the eyepiece 



> The two-leaf stuff is a real mystery. If we're thinking of the same plant, I don't see it being _H. micranthemoides_. Isn't it supposed to be from Japan?


 Maybe I'm a little careless calling my stuff "Amano's"... I've gotten this plant from Christel Kasselmann ca. 10 years ago, she told me that she has got it as H. micranthemoides for many years. The further origin is unknown. To me it seems that the 2-leaf stuff is rather widespread (but not frequent) among hobbyists in Germany but often not distinguished from the 3-leaf HM. Descriptions and pics of "Amano's pearl grass" and Ajax' plant are in line with my stuff in the submersed form (here are pics of the same clone submersed and growing emersed on a filter mat in the tank of a friend: http://www.uni-forst.gwdg.de/~dkopets/tipps.html), so I think it's the same.

Confusing: Hemianthus callitrichoides Griseb. is considered as a synonym of Micranthemum umbrosum (zipcodezoo.com etc.)... one ought to compare the type specimen with HC 'Cuba' and M. umbrosum...

I've found descriptions of H. micranthemoides (s.str.) and H. glomeratum in Pennell 1935: http://books.google.de/books?id=7lv...e=gbs_book_other_versions_r&cad=1_1#PPA161,M1 According to that the real H. micranthemoides is a cleistogamous species (flowers not opening, self-pollinating in the bud).


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## HoustonFishFanatic

Ajax, are you sure you did not get this plant from one of our NASH plant swaps. I had this plant in early 2007 in my tank. Its growth pattern is distinctly different than the 3- leaf Hemianthus macranthemoides we have in the hobby. The growth is pretty unrully compared to 3-leaf HM and not as compact. The illustration in Illustrated Flora of the Northern United States, Canada and the British Columbia show a plant with two-leaves at each node and describes it as Micranthemum macranthemoides. originally described by Nuttall as Hemianthus macranthemoides.


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## Cavan Allen

Yes, I think we're not talking about the same plant when it comes to the two-leaf. The plant to which I'm referring is much different, with a loose, upright growth pattern, a different shade of green, and other differences. I believe it's the one Neal brought back from Japan.


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## miremonster

Here's a discussion thread about the topic from 2000, I've not yet read it all:
http://fins.actwin.com/aquatic-plants/month.200012/msg00322.html


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## miremonster

OK, cultivation of possibly different 2-leaved micranthemoides-like forms under same conditions is needed. I still guess the 2-leaved ones in the hobby, also the "Amano pearl grass", are the same stuff, but I could be wrong, too. When shaded, my Hemianthus grew upright in my tank (now I keep it emersed only).

Some pics of H. "micranthemoides" with 2 leaves per node I've found in the www: 
http://www.dodo.akva.sk/foto/rastliny/hemianthus_micranthemoides_1.jpg
http://www.naturalaquariums.com/plants/hmicranthemoides.html
http://www.aquahobby.com/garden/b_micranth.php
http://www.zierfischforum.at/database1,dir_id,22,mode,display,id,287.html
http://www.h4.dion.ne.jp/~tamao/mizukusa n-paru.jpg
http://www.selvas.co.kr/front/php/product.php?product_no=2385&main_cate_no=37&display_group=1
http://www.roslinyakwariowe.net/hemiantus_zwyczajny.html
What are Your opinions?


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## miremonster

HoustonFishFanatic said:


> The illustration in Illustrated Flora of the Northern United States, Canada and the British Columbia show a plant with two-leaves at each node and describes it as Micranthemum macranthemoides. originally described by Nuttall as Hemianthus macranthemoides.


 Is this the same drawing?: http://plants.usda.gov/java/profile?symbol=MIMI6 I suspect neither the 3-leaved nor the 2-leaved H. "micranthemoides" in the hobby belong to Hemianthus micranthemoides Nuttall (= Micranthemum micr.) that's possibly extinct in the wild. As I mentioned above, this species is described as cleistogamous, with flowers remaining closed. The 2- and the 3-leaved plants I've grown emersed open their flowers, exposing stamens and stigmas.


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## miremonster

!!! : 
http://www.aquaticplantcentral.com/forumapc/local-biotopes/30605-id-hc-look-like.html
Said to be collected in NY - perhaps true Hemianthus micranthemoides, first rediscovery since 1941? Unfortunately flowers are absent.


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## Cavan Allen

miremonster said:


> What are Your opinions?


In a nutshell, I think that it's certainly _possible_ the "micranthemoides" in the hobby is actually _H. glomeratus_.

I don't think _either_ are the same as the two-leaf. I've got some of that going emersed.


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## Cavan Allen

miremonster said:


> Is this the same drawing?: http://plants.usda.gov/java/profile?symbol=MIMI6 I suspect neither the 3-leaved nor the 2-leaved H. "micranthemoides" in the hobby belong to Hemianthus micranthemoides Nuttall (= Micranthemum micr.) that's possibly extinct in the wild. As I mentioned above, this species is described as cleistogamous, with flowers remaining closed. The 2- and the 3-leaved plants I've grown emersed open their flowers, exposing stamens and stigmas.


But always cleistogamus? Some flowers can be in submersed conditions but open above water, such as those of _Blyxa aubertii_.


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## miremonster

Cavan Allen said:


> In a nutshell, I think that it's certainly _possible_ the "micranthemoides" in the hobby is actually _H. glomeratus_.


I agree!

Perhaps somebody here who collected Hemianthus in Florida (where H. glomeratus is native)?



> But always cleistogamus? Some flowers can be in submersed conditions but open above water, such as those of Blyxa aubertii.


 Yes, this character may be not very reliable. If there is newer literature about differences between these 2 spp. than Pennell 1935?

Quote from Pennell 1935: 
H. glomeratus: "Calyx lobes acute, 1/3 to 1/2 the length of the tube; mid-anterior lobe of the corolla 1/3 length of the anterior lip; flowers opening, chasmogamous."

H. micranthemoides: "Calyx lobes obtuse to obtusish, less than 1/4 the length of the tube; mid-anterior lobe of the corolla nearly 1/2 length of the anterior lip; flowers not opening, cleistogamous."


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## miremonster

I've overlooked this:


Cavan Allen said:


> I don't think _either_ are the same as the two-leaf. I've got some of that going emersed.


 Do You mean the linked photos in my posting from yesterday, and that none of them is identical with the two-leaf that You mean?


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