Persicaria pulchra (Bl.) Sojak, Preslia 46: 154 1974. (syn: Persicaria attenuata subsp. pulchra (Soják) K.L.Wilson; Polygonum pulchrum Blume);
India to SE. China and W. & Central Malesia: Andaman Is., Assam, Cambodia, China Southeast, India, Jawa, Laos, Malaya, Myanmar, Philippines, Sri Lanka, Taiwan, Thailand, Vietnam as per POWO;

Persicaria sp. from Hooghly 10/10/12 sk: 8 images.
Attaching images of Persicaria sp.

Species : Persicaria barbata (L.) H. Hara ?
Habit & Habitat : wild herb of about 2.5 feet on roadside waste place
Date : 8/10/12, 10.06 a.m.
Place : Garalgacha (Hooghly)

Very nice and clear pictures … Not aware of the species. Clearly a Polygonaceae member. I can see the ocrea. On checking the BSI Flora with me I found that two more characters might be useful for ID as per the key.
Nuts which need to be trigonous and the leaves (Which are acute and attenuate at base) which turn brown on drying and not green in P. barbata.

According to your keys this species is not P. barbata, because i think the leaf in DSCN3615.jpg does not have attenuate base.

Attaching new images of leaves of this species.
5 images.

Attaching an image of “ochrea”.
Any chance of Persicaria orientalis (L.) Spach ?

I think this can be Persicaria stagnina (Buch.-Ham. ex Meisn.) Qaiser. Very close to P. barbata but differs in having silky strigose leaves.

Thank you very much for reminding me of this long pending post, i admit that i forgot this plant.
And i strongly admit that key to Polygonum (Persicaria) is Greek or Hebrew to me.
I further admit that You have introduced me to this genus for the first time, sometimes in 1st quarter, this year.

Firstly thanks for sending me the literature of Bengal plants. I think your doubts are genuine. May I request you to check (if possible) the nuts of the plant? If they are biconvex, it would be P. pulchra (Blume) Sojak, if trigonus, P. stagnina should be correct.

Last month i visited the plant again to see if i could find any nuts as suggested earlier by … But, i couldn’t find any, in fact i was very confused where to find nutlets, all i could get is white flowers!
Certainly will visit the plant within this week and upload if i find any.
I am really indebted to you. I understand that leaving a comment in a thread by members like me is one thing and to analyze & suggest an ID is another, more so when there is a special request.
I am very grateful to you for taking so much of your time that you must have spent going through those literatures.

I tried hard but could not find any nuts or nutlets, if those are in picture no. 103 are not nuts and pic. no. 104 (original cropped) are of seeds.

Thanks for your efforts. Though the pictures are not clear.. but I guess the nuts to be trigonus. In that case your plant should be P. stagnina.

Yes, the pictures are very hazy, my camera fails to capture minute objects. Yet the nuts seems to be trigonus and the plant is Persicaria stagnina.

I am sorry to say that this plant can not be P. stagnina, f
or the ovary of this plant is not trigonous and with 3 long styles.
Attaching two photos, recorded today, of the same plant from the same population. The pictures clearly show that ovary of this plant is orbicular, and with two styles.
But it may not be P. pulchra either, for the nutlet is much smaller than 3-4mm.

Hats off to your investigation skills!
May I ask you to please wait for some more time and let the seeds get matured. Style characters are important but the seed size may vary a little.

This Persicaria species might be Persicaria lanigera (R. Br.) Sojak, as in –

Seems you are very close but shouldn’t the ochrea be glabrous if it is P. lanigera ? Requesting you to please match your photos again with the link you have provided. Another literature (Preslia 46(2): 153. 1974) treats P. lanigera as a synonym of P. lapathifolia var. lanata (Roxb.) Sojak. …..and P. lapathifolia are known to possess glabrous ochrea without bristles at apex, 2-style and broadly ovoid biconcave nuts.

First, thank you very very much for spending so much time for this post an more thanks for your patience.
Second, i missed the “glabrous ochrea” this morning, though i certainly noticed that The Plant List equates 1) Polygonum lanigerum R.Br. with Persicaria lanigera (R.Br.) Soják and 2) Polygonum lanatum Roxb. with Polygonum lapathifolium var. lanatum (Roxb.) Steward.
Third, i think we have now only two options to choose from – either it is Polygonum tomentosum Willd. (Persicaria pulchra (Blume) Soják) or it is Polygonum lanigerum R. Br. of Bengal Plants.
Except for the nut size everything seems to be pointing towards the Persicaria pulchra (Blume) Soják, But according to Flora Indica, in Polygonum lanatum R., “stipules nearly as long as the joints, striated, woolly, having their mouths lacerated, but not bearded”.
But, at the same time Roxburgh also notes that corol four-cleft. Links are –
According to F. B. I. the stem of P. lanigerum is covered with snow-white cottony tomentum, while the stem of P. tomentosum can be pubescent or glabrous.
I visited this plant again today, they are still flowering profusely, recorded more pictures today, except nuts.

Agree with you …
Now we have only two option left. Waiting to see the mature nuts one more time so that we can reach to a conclusion.

Thank you very much …, i will try to find its nuts again.

On further checking, I also feel this to be Persicaria pulchra as per references herein.




References: POWO  Catalogue of Life  The Plant List Ver.1.1  IPNI  GBIF (High resolution specimens) BSI Flora of India Checklist  Flora of China  Flora of peninsular India  Kerala plants Wikimedia Commons  Plant illustrations  Plazi   Flickr  Taieol  An Excursion Flora of Central Tamilnadu, India By K. M. Matthew

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