Piper lonchites Schult., Mant. 1: 241 1822. (syn: Piperi lonchitum (Schult.) St. Lag.);

Assam, Malaya as per POWO;

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Piper lanceaefolium by chance ?

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Piper sylvaticum ? 

http://hasbrouck.asu.edu/neotrop/plantae/imagelib/imgdetails.php?imgid=188044

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I think leaves are different in your link. 

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... is right. the veins in leaves are different.

this case- its not very clear in enface kinda picture, but i can make outa strong mid vein, and two almost parallel side veins , one on each side and faint thin veins hugging the periphery of the leaf.

in the neotropic site leavesveins are in a true "tree branching" like pattern a strong mid vein and side shoots coming out sequentially, moving axially.

in neither case we know the size of the leaves, but the venation is quite distinctive.

so our case here is not Piper lanceifolium.

It is Piper lonchites Roem & Sch.

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