# Rotala verticillaris? Nope!



## Cavan Allen

I've recently discovered that the plant going around as _Rotala verticillaris_ is not what it appeared to be and in fact, isn't even in the same family as _Rotala_ (_Lythraceae_), which has been confirmed by a botanist specializing in those genera.

Ghazanfar had some growing emersed in a tub on his front porch that had some buds forming as the weather was getting cold. I put them into a small emersed setup I have going and they flowered, as you can see here:









Compare it to the inflorescence of _Pogostemon yatabeanus_:









And that of _P. stellatus_:









I'm pretty sure I know the species but I need (as the ones pictured have faded) to be sure of a few more things. Everything I've checked so far fits. It's interesting that the real _R. verticillaris_ looks very much like it, apart from its sessile (right up against the stem), solitary flowers.

I have been informed that this species is now being sold as a _Pogostemon_ in Japan.


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## Tex Gal

That is a beautiful flower! It sure looks like you are on the right track. It's amazing what you all can do! Thanks!


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## plantkeeper

Well this clear up my mystery. Nice work.

I am going to stick some of this in my emersed setup, pretty inflorescence.


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## Crispino Ramos

some friends call it Pogostemon erectum


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## Cavan Allen

That's the correct name. Its inflorescences are not like any _Rotala_ and it does match _P. erectum_.


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## hooha

For those of you who aren't as edumacated like me 

Rotala rotundifolia flower:









Pogostemon erectum flower (the plant formerly know as Rotala verticillaris):


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## Cavan Allen

If you look closely at the flowers of the _Pogostemon_, you'll notice that the filaments of the stamens have trichomes (hairs). No species in the entire _Lythraceae_ family has that feature (that was what I meant to say above). Additionally, the flowers of real _R. verticillaris_ are quite small and are right up against the stem at the nodes, totally unlike the flowers shown previously.

I noticed too, that the Japanese site Grassy Aqua lists it as "Rotala cf. verticillaris" (cf meaning similar to) and gives the place of collection as in the state of Maharashtra, in Western peninsular India (_P. erectum_ is endemic to this area), where _R. verticillaris_ does not grow (it does grow in the Southeastern side of the peninsula and in Sri Lanka). Not conclusive by itself, but certainly interesting.

In this case, I was fortunate to have not only a good description (Aquatic and Wetland Plants of India by C.D.K. Cook), but also well-preserved actual specimens to which I could compare my flowering material. Very neat stuff.


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## Cavan Allen

I ran across this photo of _P. erectum_ in its natural habitat (_P. deccanescens_ is a synonym):

__
https://flic.kr/p/2924384477


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## davemonkey

Wow! That's quite a site to see a species dominate like that. All the wetlands here are a hodge-podge of different plants. The only ones with a 'majority species' are those getting overtaken by AlligatorWeed.

-Dave


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## apm

those are crazy colours, really cool camera work. I just got my canon xsi.. im def not there yet.. any tips?


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