# R. indica<--> R. rotundifolia is there a difference?



## neonfish3 (Feb 12, 2004)

I thought they were the same plant with different epithets. As in the name was changing from one to the other.

I answered a ID question on another board for a plant I thought was R. indica. I was corrected in that it was R. rotundifolia.

As far as the Iron Aquascapers Challenge is concerned will it matter?

From the USGS -->Rotala rotundifolia produces flowers on terminal spikes (racemes) and differs from a previously introduced species, Rotala indica, which is an annual species with shorter, lateral flower spikes. 

I'm including pics of my R. indica? and the plant I was corrected on.


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## Error (Apr 16, 2004)

The difference between the two species has never been made entirely clear to me either. I think it is safe to assume that just about every plant in aquaristic cultivation (at least in the US) is R. rotundifolia.

R. indica does indeed seem to be a valid species name, but I see no way for the aquarist to easily differentiate between it and its congeners.

I know alot of the Rotala that I've been seeing at local shops has been grown emersed and has round leaves. I think this may imply R. rotundifolia, but I don't know what emersed plants of R. indica look like.

I don't think it should matter for contest since there's really no way to tell anyway.


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## jerseyjay (Jan 25, 2004)

Info on _Rotala rotundifolia_

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http://cars.er.usgs.gov/Nonindigenous_Species/Rotala_rotundifolia/rotala_rotundifolia.html

_References: 
Reese, N.L. and R.R. Haynes. 2002. Noteworthy Collections: Alabama. Castanea 67:216.
Cook. C.D.K. 1976. A revision of the genus Rotala. Boissiera 29:1-156_

--------------------------------

_"Rotala rotundifolia was introduced in 1960 as Rotala indica. This however, is a different species."_

Christel Kasselmann 
"Aquarium Plants"
page 412


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## neonfish3 (Feb 12, 2004)

OK., they are different species. Is mine R indica or rotundifolia? What is the other pic?
What about the contest?


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## tsunami (Jan 24, 2004)

Unless you get the plants in your photo to flower, there really isn't a way to correctly identify your plants. That's the only way I know of to differentiate Rotala indica from Rotala rotundifolia. The Rotala rotundifolia will bear bunches of flowers at the end of a flower spike while Rotala indica will bear solitary flowers on the stem internodes.

It really does not matter for the contest.

Carlos


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## Roger Miller (Jun 19, 2004)

A few months back Oliver Knott posted a picture in his rare plants gallery of a fiery red plant that he labeled "R. indica". It appears to me to be a different plant from our usual R. rotundifolia.

His photo is at:

http://www.pbase.com/plantella/ttank

Roger Miller


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## Freemann (Mar 19, 2004)

*Indica versus Rotundifolia*

Ok here are 2 photos of my rotalas.
















Notice that indica has slender longer leaves and the reds are really reds.
Also Indica is much more agressive to move towards the surface and grow horizontal there with rhizomes in every node.


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## dennis (Mar 1, 2004)

Is it me or does the rotundifolia have 3 leaves per node and that indica have 2? I must be seeing the 2nd photo wrong.

Actuall I just checked my "indica" 2 leaves per nod and the nodes are alternating (at each node the leave come in a 90` from the one before it). I guess the rotundifolia pic is... No offense but is that first one really rotundifolia?


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## tsunami (Jan 24, 2004)

I have seen my Rotala rotundifolia grow with both of this growth forms, Freeman...

I have seen my Rotala go from egg shaped leaved at 4 leaves per node to fiery red with two leaves per node, and everything in between. I don't physical characteristics are a good way to differentiate between these plants.

Roger: Dennerle does produce a plant called Rotala rotundifolia 'colorata.' Perhaps that is Oliver's plant?

Carlos


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## Freemann (Mar 19, 2004)

From Aquarium Plants - Christel Kasselmann:

*Rotala rotundifolia*
(Roxburgh) Koehne (1880)

_Family:_ Lythraceae.
_Synonyms:_ Ammania rotundifolia Buchanan-Hamilton (1820), and others.
_Etymology:_ Rotala: see Rotala macrandra; rotwulifolia: round-leaved.
_Distribution:_ Southeast Asia (India to Japan).
_Description:_ Marsh plant with creeping, ascendent or drifting shoots, up to about 70 cm long. Emersed leaves decussate, sessile or short petiolate, entire, obovate to round, about 1( - 2) cm long, upperside olive green, underside slightly reddish. Submersed shoots erect, very branched. *Leaves opposite or in 3-4-merous whorls.* Blade lanceolate, in drifting shoots also almost round, up to 2.2 cm in length, upperside olive green to reddish, underside pale to a strong violet color.
Inflorescence densely flowered, at the base often branched raceme, up to 11 cm petiolate. On each node, 2 flowers with a cordate or almost round up to 6-mm thick bract. Solitary flower short petiolate. Calyx with 4 triangular calyx-lobes without appendage. Bracts about 1 mm; 4 petals, pale purple, obovate, about 1.5 mm long; 4 stamens, about 1.5 mm long, not longer than the calyx-lobes. Style 0.5-1.5 mm long; stigma capitate. Ovary globular. Capsule about 1.5 mm, with 4 valves opening. Culture: An especially recommendable, adaptable, decorative and quick-growing stem plant, good lighting is necessary to achieve strong, reddish shoots. The species will tolerate large fluctuations in hardness and pH-values. Optimum temperature range is 24-28 °C. Propagation is unproblematic through lateral shoots. The plants do not display good protruding growth from the water so that adaptation to emersed cultivation is not easy. However, once this has been established cultivation in the paludarium or greenhouse is so rapid that the species can become a real weed. Inflorescences occur only above the water surface.
_Ecology:_ The species grows in marshy areas and often in cool mountain regions, in China up to an altitude of 2650 m.
_Other:_ *Was introduced in 1960 as Rotala indica. This, however, is a different species.*

And From the Complete Guide to Water Plants - Muhlberg:

*Rotala rotundifolia (Roxb.) Koehne*

The species was named Ammannia rotundifolia by Roxburgh in 1820. Koehne moved it to the genus Rotala in 1880. In aquaristic literature it is often denoted as R.indica, but this is an error.
_Distribution:_ South-east Asiatic mainland.
_Characteristics:_ A herbaceous plant with elongated shoot axes and leaves arranged opposite and decussate, creeping horizontally on wet soil and growing erect submerged. Leaves sessile. Submerged leaves very variable, linear, lanceolate, blunt, elliptical, egg-shaped or almost roundish, up to 1.5 cm long and up to 4 mm wide, upperside pale-green, underside whitish-green to reddish. Aerial leaves always round, dark-green. Inflorescence is composed of several spikes, terminal. Flowers small, with red petals of the corolla.
_Cultivation and Propagation:_ A small-leafed, undemanding plant, to be used in a clump among larger plants in the middle part of the tank, but it also looks well in the background. It is equally suitable for being planted in the corners of the foreground. In an aquarium shoots often grow creeping along the substrate and branch intensively. This species should not be too much in the shade. Temperature just above 18 °C. Propagation from cuttings.

*Rotala indica (Willd.) Koehne*

The species was named Peplis indica by Willdenow in 1799 and moved to the genus Rotala by Koehne in 1880.
_Distribution:_ South-East Asia; it has become naturalized in the rice fields of northern Italy.
_Characteristics:_ Herbaceous plants with elongated shoot axes, creeping horizontally on wet soil or growing erect when submerged. Leaves arranged opposite and decussate, sessile. Submerged leaves linear to slightly spatulate, up to 1 cm long and up to 3 mm wide, upperside pale-green, underside whitish-green. Flowers solitary in leaf axils of aerial shoots, very small with pink petals of the corolla.
_Cultivation and Propagation:_ As described for R. rotundifolia. However, the species does not grow satisfactorily everywhere.

More on the 2 species from others:

Rotala rotundifolia produces flowers on terminal spikes (racemes) and differs from a previously introduced species, Rotala indica, which is an annual species with shorter, lateral flower spikes.









Rotundifolia flowering (Photo: Muhlberg - The complete guide to aquarium plants)

Dennis
Rotundifolia can have 2 or more leaves per node (notice bold reference in Kasselman) it seems I have the 3 leaf variety

Carlos
The 2 plants I have here are easily differentiated even on the same tank.
Both leaf shape and color.


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## Error (Apr 16, 2004)

Given those descriptions, I think the only thing that can be safely concluded is that R. indica does not have 3-4 merous whorls.

I have attempted to flower every variety of R. "indica" and "rotundifolia" I have come across, and every flower I've ever gotten has been purple, despite the plant's submersed form having color between red, green and orange, with any combination of leaf arrangements and shapes, including ones that change with tank conditions. I think it's safe to assume that R. indica is not currently in widespread cultivation in the US.

However, these plants are not hard to get to flower. Just fill a small tank or basin with an inch of garden or topsoil, fill this with water so it's about an inch deep above the soil, plant a few stems and stick it outside in a sunny locale. I add Gambusia to the buckets and tanks that I plant because of West Nile.


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