§ Palathrin (Palath = Iris) (RS:432) – the ’Gladden’ river
Tolkien wrote in Let:297 about the flower gladden:
[…] the local names Gladden River, and the Gladden Fields, which contains A.S. glædene ’iris’, in my book supposed to refer to the ’yellow flag’ growing in streams and marshes: sc. iris pseudacorus, and not iris foetidissima
The later name of this flower, ninglor, is translated as ’golden water-flower’ (UT:450); consisting out of S. nîn ’wet’ < nēnā (Silm:nen, PE17:52) and glor ’gold’ (GLAW(-R)-). This earlier name, however, contains no identifiable element meaning ’gold’ or ’yellow’. The word palath (PAL-) means ’surface’ in Noldorin instead; the stem is glossed ’wide (open)’ and produces words like Q. palu-, palya- ’open wide, spread, expand, extend’, N. pelio ’spread’. So perhaps palath is the *’wide open flower’ with reference to its long and broad petals? Note also that palath also appears with the original meaning in Palath Nenui ’Wetwang’ (’wang’ = ’field, flat area’), see below (2.38).
Here, palath is given the adjectival ending -rin comparable for instance to celebrin ’of silver’ < celeb ’silver’ (KYELEP-,TELEP-). See the river Celebrin above (1.10).