taproot - the main root of a plant

tuck-and-roll - | | | | | (that kind of upholstery on car seats is called tuck-and-roll; didn't know the word for it)
( more words... )

phthalo in this context - as a modifier for 'darkness', referring to the evening sky - appears to be short for 'phthalocyanine'. According to wikipedia, 'Phthalocyanine is an intensely blue-green coloured aromatic macrocyclic compound that is widely used in dyeing.' According to AHD, the word covers several blue or green organic compounds used in enamels, printing inks, linoleum, and plastics.

I admit to doubt as to whether the viewpoint character would know this word.

'Lour' is a variant of 'lower'. In this case, it was being used in the noun sense of 'a threatening or sullen look' or 'a dark and ominous look'. I wouldn't have applied it to summer *heat*, myself, although I can understand applying it to clouds during such weather. (Credit to The American Heritage Dictionary for explaining to me what it meant.)

'Like the man dreaming, who feels even in sleep the refreshing storm break the lour of summer heat...'
- chapter 1 of The Silent Tower by Barbara Hambly

As for 'ophidian', it means 'snakelike'. Nothing to do with obsidian at all.

(As for 'water strider', that's a kind of insect that appears to walk on water. Yes, they're the ones also known as 'Jesus bugs'. The chapter that uses this term is being told from the viewpoint of a character who has never heard of Christianity, hence the term being used.)

The narrator appears to use the English rather than the Spanish pronunciation of 'Simon', judging from the excerpt I listened to earlier this evening. Granted, it would probably help if the English text put in the accent mark.