Oleandra undulata

Oleandra undulata (Willd.) Ching, Lingnan Sci. J. 12(4): 565 1933. (syn: Oleandra cumingii Hook. & Bak.; Oleandra cumingii var. longipes Hook.; Oleandra pubescens Copel.; Polypodium undulatum Willd.);
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S. India, China (Yunnan) and Indo-China: Cambodia, China South-Central, India, Laos, Myanmar, Thailand, Vietnam as per POWO;
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India (Manipur, Nagaland, Mizoram), Nepal, Myanmar [Burma], Thailand (widespread), Laos, Cambodia, Vietnam, China (Yunnan) as per Catalogue of Life;
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SK523 14 MAY-2017:ID : 3 posts by 2 authors. Attachments (4)
Location: Taplejung, Nepal
Date: 18 April 2017
Altitude: 6000 ft.
Fern…???

This is Oleandra undulata, which was not known in Nepal until I found it a decade or so ago.  Very nice thing – I have a photo taken at Pokhara (Sarankot) just like that one!

 

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Oleandra wallichii (Hook.) C. Presl : 4 posts by 3 authors. Attachments (3)
Oleandra wallichii (Hook.) C. Presl, a wild fern from Darjeeling area with thin elongated runners.

We have similar looking ferns Lepisorus spp. in Shimla.

Sorry, but no, it is not O. wallichii, but O. undulata – while being closer and superficially similar to O. wallichii the two are quite different species and once one knows the difference and becomes familiar with BOTH, they can readily be recognised.
O. wallichii is at higher altitude and common around Darjeeling, as also in Nepal and throughout the Indo-Himalaya.  It has a shorter lower part to the stipe, beneath the articulation, often a wider and more abrupt base, more of the single, separate fronds and the main distinction is in the rhizome-scales. Those of O. wallichii have prominent dark or blackish bases, but those of O. undulata are predominantly brown. The rhizome-apices look quite different.  I illustrated Hooker’s fine coloured drawing of O. wallichii in one of my books, “The First Botanical Collectors in Nepal” and of course it is a much commoner and very well known, widely distributed epiphyte on trees in the higher Himalaya, usually 1900-2000 m upwards.
O. undulata is rare and occurs mostly around the 1000 m. mark and is almost always on rock-faces, a lithophyte.  In fact it was not known as far west as Nepal, when I discovered it there and less than half a dozen collections (misidentified) had been made.
Please be aware that there are the two species and the resemblance is only superficial.