om vacadbhuve namah

In this verse, Kavyakantha Ganapati Muni, as the Seer, reveals the bIjAksharas (seed syllables and/or letters) which make up Sri Ramana Maharshi's special mantra. This mantra reveals various correspondences and is said to be endowed with Sakti (power). 

vedAdi - beginning (and end) of the Vedas - bIja - 'om' 

pAka damana (indra) uttara - mightier than Indra, the subduer of the demoncalled PAka (symbolic of the overcoming of ignorance). Sri Maharshi lies beyond even the Lord of the senses. Lord Indra's bIja is 'la'. When we go beyond this we find... bIja - 'va'

kacchapeSa - kurmeSa - Lord of tortoises - supporter of the Earth and all its jIvas - Rudra - bIja - 'ca'

dharAdhara - the Hill, Mount Arunachala - The Hill of Dawn. Supporter of the Universe. Epithet of Siva and symbolic of transcendence. (note: dharAdhara is also an epithet of Vishnu as preserver) - bIja - 'd'

sushupti - known as sleep - Here it represents Sakti - bIja - 'bha' (note: the vowel 'a' is omitted.)

amareSvara - Lord of Gods (Rudra) - bIja - 'u'

amRta - toyabIja - water, syllable of offering signifying dative case (along with next letter) - 'v'

sUkshmAmRtA - Siva Sakti - bIja - 'e'

praNatyA (pra-Nati) - obeisance/surrender of body and mind with humility - 'namaH'

This spells out the Guru mantra - 'om vacadbhuve namaH' - 'Obeisance to that 'place' of Being from whence the Word arises (and sets)'