Attached images are Pandanus sp. (?)Please ID for it.

Date : 21.12.2012

Location: Kamrup district

Family : Pandanaceae

Genus & species : Pandanus sp. (?)

Habitat: Grows wild on. roky area near the stream.

Habit : Herb
Leaf : Spine present on one side of the margin.
Flower : Not seen

In my opinion, it is Pandanus polycephalus

The species is belong to genus Pandanus Only.
Name of species is Pandanus nepalensis.

Why WCSP and Catalogue of Life give Pandanus nepalensis H.St.John as syn. of Pandanus furcatus Roxb.?

Actually that is mistake. Pandanus furcatus found only in southern India. And nepalensis in North eastern region.
Details you will get in Indian pandanaceae book. 

It looks like Benstonea (earlier Pandanus) thwatsii

Pandanus nepalensis H.St.John  is the syn. of Pandanus furcatus Roxb., and this is not the correct ID

This is rather Benstonea foetida (Roxb.) Callm. & Buerki Syn. Pandanus foetidus Roxb.

… has earlier stated it to be Benstonea thwaitesii (Martelli) Callm. & Buerki

That was just  a suggestion, not the confirmation !

Please see : https://www.gbif.org/occurrence/4167813813

Is it Benstonea thwatsii or Benstonea foetida (Roxb.) Callm. & Buerki ?

It is very difficult to identify on the basis of only leaf structure. Definitely it is not Benstonea foetida. Benstonea thwatsii has very long leaves more than 5 m but the base of leaf is not pigmented so may not be Benstonea thwatsii also. Please send fruit pic for proper identification.

I want to inform you the latest data available on
Occurrence of Species Under Pandanaceae in Assam
          According to ‘Flowering plants of India –An Annotated Checklist (Monocotyledon)’, BSI [Mao and Dash 2020]the distribution of species under family Pandanaceae in Assam are Pandanus assamensis, P. diversus, P. furcatus, P. martinianus, P. unguifer. On the other hand Assam’s flora (Chowdury 2005), ‘Plant Diversity of Assam – A Checklist of Angiosperm and Gymnosperms’ (Barooah and Ahmed, 2014)and ‘Plantes Assam- Current Taxonomic Version of the Vascular Plants of Assam (Chowdhury,2021) includes two species of  Benstonea foetida(= Pandanus foetidus)Benstonea humilis and  other spp. of Pandanus viz P. furcatus, P. humilis, P. tectorius, P. unguifer, P.amaryllifolius and Pandanus odorifer  in Assam under Familly Pandanaceae.
Sir, I had collected this specimen in the year 2012 (twelve years back). The leaf of specimen shown in the images has spine in one margin not on both margin. But in Benstonea thwatsii or Benstonea foetida both margin of the leaf possess spine. If I could get the fruits of this specimen from the site I will definitely upload it.