Rheum spiciforme Royle, Ill. Bot. Himal. Mts. 1: 315, 318, pl. 78 315 1839. (Syn: Rheum scaberrimum Lingelsh.) as per The Plant List Ver.1.1 ; 
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Rheum spiciforme Royle, Ill. bot. Himal. Mts. 1(9):318. 1836; 2(4): t. 78. 1834 (Syn: (=) Rheum przewalskyi Losinsk.; (=) Rheum rhizostachyum Schrenk; (=) Rheum rhomboideum Losinsk.) as per GRIN;
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Common name: Spiked Rhubarb • Ladakhi: ལཆུ Lachhu
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Ladakh, August 2022 :: Rheum for ID :: ARK2022-178:

This was near Lachung la in Ladakh in August 2022.
Requested to please provide ID.

Looks like Rheum spiciforme Royle.


Going by Distribution in the Checklist of Ladakh, Saroj ji may be right.

Although it is quite close with Rheum moorcroftianum Royle, as per keys from Flora of China:
8 (7) Leaves broadly ovate or ovate-elliptic, both surfaces hairy, apex obtuse; fruit ellipsoid; perianth green. 30 Rspiciforme
+ Leaves ovate or triangular-ovate, glabrous or hairy abaxially, apex obtuse to acute; fruit ovoid or broadly ovoid; perianth yellow-white. (9)
9 (8) Leaves ovate, glabrous; panicle 2-4(or 5)-branched from base; fruit ovoid, 7-8 × 5-6 mm, wings 1-1.5 mm wide. 31 Rmoorcroftianum
+ Leaves triangular-ovate, pubescent abaxially; panicle much branched from base; fruit broadly ovoid, 7.5-8.5 × 7-8 mm, wings ca. 2.5 mm wide. 35 Rreticulatum
Are both surfaces hairy ?
Pl. check.


Yes, R. spiciforme looks more likely.


Are both surfaces of leaves hairy?


attaching a close up of the leaves, if it helps.
I do not think they are hairy.


May be difficult to judge from photos sometimes, as keys were usually made based on herbarium specimens.

Furthermore

Flora of China says: both surfaces papilliferous or abaxially glabrous; 
Flora of Pakistan says: usually glabrous;



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