useless trivia: What Word Means: A Spiny South African Desert Shrub?

Questions

- Abbreviation of pizzicato.?

(It.) - Indication to pluck notes on a bowed string instrument. Abbreviation pizz.?

- A closing cadence consisting of a progression of the subdominant (chord IV) to the tonic (Chord I) sounding like 'Amen'.?

(from Lat. cantus planus) - Medieval church music usually describing the gregorian chant which still survives today in the Roman Catholic church. It consists of a single, unaccompanied vocal line in free rhythm like speech with no regular bar lengths.?

(Gk ., ' breath ' ) - A type of florid passage in plainsong sung to a single vowel.?